Email Clients & Email AI Arena
Shortwave vs Fastmail
Fastmail
Fastmail Pty Ltd
Shortwave wins · 17–17 (18 drawn)
Accounts openness — stories about accounts openness in this arenaAccounts openness
Stories about accounts openness in this arena
Multi account
switcherConnect several accounts across providers — Gmail, Microsoft 365, IMAP — and work them from one place
weight 3 · round to FastmailShortwavenone0/10No evidence Shortwave supports connecting multiple providers (Gmail, Microsoft 365, IMAP) from one inbox; in fact the founder explicitly states they integrate only with Gmail's APIs ('not IMAP'), and a user confirms 'it only works with Google servers.' This directly contradicts the multi-provider switcher story rather than merely lacking support for it.
- [community] “Founder: We integrate with Gmail's APIs (not IMAP) to enable faster real-time updates, better latency compensation, offline handling, bundle…”
- [community] “Security-focused user: 'there is no way I could use a web mail client for security reasons (as a security consultant, we use PGP a lot and n…”
Fastmail explicitly documents importing mail from other providers and 'fetching mail from Gmail like a mail client' (IMAP-style pull), plus a 'Logging in to multiple accounts' feature and a dedicated Gmail-migration guide, and community reports confirm smooth Gmail-to-Fastmail migrations. However, evidence never mentions Microsoft 365/Exchange connectivity specifically, doesn't show a true unified single-inbox view merging external accounts (vs. separate logins), and one commenter notes migrating filters/rules doesn't come over cleanly. Missing for 10: explicit Microsoft 365/M365 account linking, detail on whether multiple accounts appear merged in one inbox view, and independent verification of multi-provider IMAP account aggregation beyond Gmail.
- [community] “As an alternative to forwarding, you can also configure Fastmail to fetch mail from (and send via) Gmail like a mail client.”
- [community] “Fastmail has an easy migration tool as well if you don't want to go the IMAP route. Now, migrating filters and rules over on the other hand.…”
- [claimed-docs] “Import your mail”
- [claimed-docs] “Logging in to multiple accounts”
- [claimed-docs] “Move from Gmail”
Portability
switcherMy mail stays reachable over open protocols and standard formats — IMAP/JMAP/SMTP access and standards-based export — so no client can lock me in
weight 2 · round to FastmailShortwavenone0/10Shortwave's own founder states they integrate via Gmail's proprietary APIs 'not IMAP,' and there is no mention anywhere in docs of JMAP, SMTP-level access, or standards-based export tooling — the product only works atop Google's servers (also confirmed by a security-focused user noting 'it only works with Google servers'). No evidence of any open-protocol mail access or portable export path exists in the pack.
- [community] “Founder: We integrate with Gmail's APIs (not IMAP) to enable faster real-time updates, better latency compensation, offline handling, bundle…”
- [community] “Security-focused user: 'there is no way I could use a web mail client for security reasons (as a security consultant, we use PGP a lot and n…”
Fastmail documents JMAP (open standard) and IMAP/SMTP access via API tokens/app passwords, plus import/export tooling for migration, and community reports confirm SMTP/IMAP interoperability with other providers (e.g., fetching Gmail via IMAP, app passwords for SMTP). This directly supports open-protocol reachability and avoiding lock-in. Missing for 10: explicit documentation of full mail export/backup format standards (e.g., mbox/EML export) and independent verification of IMAP feature parity beyond anecdotal mentions.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “JMAP is an open standard any organisation can implement, not more proprietary lock-in from big tech companies.”
- [claimed-docs] “Open source and standards | Fastmail”
- [claimed-docs] “API tokens”
- [claimed-docs] “Import your mail”
- [community] “As an alternative to forwarding, you can also configure Fastmail to fetch mail from (and send via) Gmail like a mail client.”
- [community] “I just use SMTP for this (with FastMail). FastMail is not really intended for [transactional emails at scale] as the limits and the like don…”
- [community] “Fastmail has an easy migration tool as well if you don't want to go the IMAP route. Now, migrating filters and rules over on the other hand.…”
switcherSelf-host the email app and keep the mail pipeline under my own control
weight 1 · round drawnShortwavenone0/10Shortwave is a cloud-hosted email client that syncs data to its own servers and works only with Gmail/Google servers (per community reports), with no documentation of any self-hosting option, on-prem deployment, or open-source pipeline; probes for docs/API specs also return 404s, indicating no infrastructure exposed for self-hosting.
- [community] “Security-focused user: 'there is no way I could use a web mail client for security reasons (as a security consultant, we use PGP a lot and n…”
- [community] “Privacy concern: user worried about syncing sensitive emails (OTPs, bank/SSN emails) to Shortwave's servers and wished for a denylist to exc…”
- [community] “User quoted privacy policy allowing sharing of email content/metadata with third-party vendors and said 'Hard pass' given business email con…”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.shortwave.com/llms.txt”
- [probe] “PROBE docs-md: HTTP 404 at https://www.shortwave.com/docs/.md”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
Agenticness — how well agents can access and operate the productAgenticness
How well agents can access and operate the product
Agent access
ai-native userPoint an agent at llms.txt or agent-oriented docs
weight 2 · round drawnShortwavenone0/10Direct probes show no llms.txt or agent-oriented docs endpoint exists (404s across llms.txt, docs-md, openapi paths), and no other evidence mentions such agent-facing documentation.
Fastmailnone0/10A direct probe confirms no llms.txt exists (404) and no openapi/agent-oriented discovery docs were found either; while JMAP API docs exist, there is no evidence of an llms.txt or agent-oriented documentation entry point.
ai-native userRun the product headlessly / in CI for automation
weight 2 · round to FastmailShortwavenone0/10The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)
Fastmail exposes a documented JMAP API and API tokens/OAuth for programmatic access (fastmail-docs-1,2,5,22,40), and community evidence confirms it can be driven via SMTP/app passwords for scripted/automated sending (fastmail-comm-11), which supports headless use in scripts or CI. However, there is no explicit CI/headless-mode documentation, no official CLI, and community feedback notes it isn't built for large-scale automated/transactional use. Missing for 10: dedicated CI/automation documentation or examples, an official CLI, and confirmation of headless reliability at scale.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement. Works with what you already have.”
- [claimed-docs] “API tokens”
- [claimed-docs] “API Documentation”
- [community] “I just use SMTP for this (with FastMail). FastMail is not really intended for [transactional emails at scale] as the limits and the like don…”
ai-native userPlug MCP servers into this product so it can use their tools
weight 3 · round to ShortwaveShortwave explicitly documents connecting to any MCP server via 'Add custom integration' to let its AI Assistant use those tools, with first-party blog docs and pricing page confirming MCP support alongside built-in integrations. Missing for 10: independent hands-on verification of the MCP setup flow and no detail on tool-call reliability/limits beyond marketing docs.
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [claimed-docs] “Just click "Add custom integration" and point to an MCP server of your choice — or even create your own.”
- [claimed-docs] “AI Integrations for Shortwave—a powerful new feature that connects our AI Assistant to all your business applications, letting you accomplis…”
- [claimed-docs] “Connect the AI with your favorite apps and services for enhanced productivity workflows through built-in integrations or MCP”
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [community] “Security vendor blog highlighted that Shortwave's AI Email with MCP integration 'opens up rich capabilities—but also new attack surfaces,' f…”
ai-native userConnect an agent via an official MCP server
weight 3 · round drawnShortwavenone0/10Shortwave documents letting its own AI Assistant connect out to third-party MCP servers ('Add custom integration', point to an MCP server of your choice) — this is MCP-client behavior, not Shortwave exposing an official MCP server that external agents could connect to. As a SaaS email product, offering an official MCP server for outside agents is a fair, applicable axis, but no evidence pack item shows such a server (docs/openapi/llms.txt probes all 404).
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [claimed-docs] “Just click "Add custom integration" and point to an MCP server of your choice — or even create your own.”
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.shortwave.com/llms.txt”
- [probe] “PROBE docs-md: HTTP 404 at https://www.shortwave.com/docs/.md”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
Fastmailnone0/10Fastmail exposes JMAP and API tokens for developers, but there is no evidence of an official MCP server or endpoint that lets AI agents connect natively; probes for machine-readable spec files (llms.txt, openapi) both return 404.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “API tokens”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.fastmail.help/llms.txt”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.fastmail.help/openapi.json, https://www.fastmail.help/swagger.json, https://www.fastmail…”
ai-native userDrive the product through a documented public API
weight 3 · round to FastmailShortwavenone0/10Shortwave's evidence only shows it acting as an MCP *client* (connecting its AI Assistant to other apps' MCP servers) or integrating with third-party APIs like Zapier/GitHub — none of this constitutes Shortwave itself exposing a documented public API for external developers to drive the product. Direct probes for llms.txt, docs-as-markdown, and OpenAPI/Swagger specs all returned 404s, confirming no discoverable public API surface.
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [claimed-docs] “Just click "Add custom integration" and point to an MCP server of your choice — or even create your own.”
- [claimed-docs] “Connect the AI with your favorite apps and services for enhanced productivity workflows through built-in integrations or MCP”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.shortwave.com/llms.txt”
- [probe] “PROBE docs-md: HTTP 404 at https://www.shortwave.com/docs/.md”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
Fastmail publishes JMAP, an open, documented API protocol with a discoverable session endpoint, standard OAuth2/Bearer auth, API tokens, push via EventSource/WebPush, and a dedicated dev docs page (fastmail.com/dev), giving AI-native users a clear, standards-based way to programmatically drive the product. Missing for 10: no evidence of an OpenAPI/Swagger spec or llms.txt (probes returned 404s) and no independent third-party corroboration of API robustness beyond vendor docs.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement. Works with what you already have.”
- [claimed-docs] “Get instant push via EventSource — one connection, all mailboxes. Or use WebPush for mobile-compatible push, no permanent connection require…”
- [claimed-docs] “Sync changes more easily, more efficiently, and much, much faster. A single HTTP roundtrip is often all that's required.”
- [claimed-docs] “API tokens”
- [claimed-docs] “POST a `methodCalls` array. Query, fetch, and send, all in one HTTP request.”
- [claimed-docs] “API Documentation”
- [claimed-docs] “Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement.”
ai-native userIssue scoped/least-privilege API credentials for an agent
weight 2 · round to FastmailShortwavenone0/10Shortwave's evidence covers MCP/app integrations and AI assistant features, but there is no mention of scoped or least-privilege API credential issuance, API key management, or granular permission controls for agents; probes confirm no public API/OpenAPI spec exists. Community comments even note complaints about over-broad permission requests rather than scoped credentials, reinforcing absence of this capability.
- [probe] “PROBE llms.txt: HTTP 404 at https://www.shortwave.com/llms.txt”
- [probe] “PROBE docs-md: HTTP 404 at https://www.shortwave.com/docs/.md”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
- [community] “User complaint: 'all these apps either want gmail way too many gmail permissions, and/or are hosted... I'm trying to get rid of gmail lol.'”
Fastmail provides API tokens (fastmail-docs-5/22) and OAuth2/Bearer token support (fastmail-docs-2/41) for JMAP access, and community evidence confirms real-world scoped 'app passwords' limited to a single protocol like SMTP (fastmail-comm-11), showing least-privilege credential issuance works in practice. However, the docs are only titles with no detail on fine-grained scope configuration for agent-specific use cases, and there's no explicit agent/AI-oriented credential guidance. Missing for 10: detailed scope/permission granularity documentation, explicit agent-use-case guidance, and independent hands-on verification of scoping API tokens (not just app passwords) for AI agents.
- [claimed-docs] “API tokens”
- [claimed-docs] “API tokens – Fastmail”
- [claimed-docs] “Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement. Works with what you already have.”
- [claimed-docs] “Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement.”
- [community] “I just use SMTP for this (with FastMail). FastMail is not really intended for [transactional emails at scale] as the limits and the like don…”
ai-native userBuild against official SDKs
weight 2 · round drawnShortwavenone0/10No evidence of any official SDKs for developers; probes for llms.txt, docs.md, and OpenAPI/swagger specs all returned 404, and the evidence pack only documents MCP-based integrations for end-user workflows (Slack, Notion, Zapier) rather than a developer SDK.
Fastmailnone0/10Fastmail documents the JMAP protocol and a developer API page, but the evidence never mentions any official SDKs (client libraries) for languages/frameworks — only raw protocol specs, API tokens, and a dev docs page. Probes for machine-readable API discovery (llms.txt, openapi) also 404, reinforcing the absence of packaged SDK tooling.
- [claimed-docs] “API Documentation”
- [claimed-docs] “API tokens”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.fastmail.help/llms.txt”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.fastmail.help/openapi.json, https://www.fastmail.help/swagger.json, https://www.fastmail…”
ai-native userSubscribe to events via webhooks
weight 2 · round to FastmailShortwavenone0/10Shortwave's evidence covers triggers, MCP integrations, and Zapier connections, but nothing describes outbound webhooks that let an AI-native user subscribe to Shortwave events; no webhook API, subscription endpoint, or event schema is documented, and OpenAPI/llms.txt probes returned 404s.
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
Fastmail's JMAP API supports push/event notification via EventSource (SSE) and WebPush, which lets clients subscribe to mailbox changes without polling — a webhook-adjacent mechanism (docs-3, docs-19). However, there's no explicit documentation of a classic webhook (HTTP callback URL registration) API, and no independent/hands-on confirmation of setting up such subscriptions. Missing for 10: explicit webhook callback-URL registration docs, third-party confirmation of push reliability, and any mention of 'webhook' terminology in official docs.
- [claimed-docs] “Get instant push via EventSource — one connection, all mailboxes. Or use WebPush for mobile-compatible push, no permanent connection require…”
- [claimed-docs] “Get instant push via EventSource — one connection, all mailboxes.”
- [claimed-docs] “POST a `methodCalls` array. Query, fetch, and send, all in one HTTP request.”
- [claimed-docs] “API Documentation”
Agentic features
ai-native userGet AI-generated insights and suggestions from my data inside the product
weight 2 · round to ShortwaveShortwave delivers AI-generated insights directly in-product: Instant Summaries appear atop threads, AI Assistant reads threads/searches history/checks calendar to surface answers, Ghostwriter offers inline autocomplete suggestions, and custom AI filters/triggers auto-label and organize emails based on AI analysis. These are well-documented first-party features spanning summarization, suggestion, and automated insight generation across the inbox. Missing for 10: independent hands-on validation of insight quality/accuracy and no third-party review confirming these AI insights work reliably in practice beyond vendor claims.
- [claimed-docs] “Instant Summaries show up at the very top of your email threads the instant you open them.”
- [claimed-docs] “Instant Summaries show up at the very top of your email threads the **instant** you open them.”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more.”
- [claimed-docs] “you’ll see suggestions presented to you automatically as you draft emails. Just press ‘tab’ to complete.”
- [claimed-docs] “you’ll see suggestions presented to you automatically as you draft emails. Just press ‘tab’ to complete”
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Identify important emails & todos with a single click. Sweep away the rest.”
ai-native userSet up automations that run autonomously in the background
weight 2 · round to ShortwaveShortwave explicitly supports triggers that draft replies, add comments, organize threads into todos when emails arrive, plus custom AI filters running as background scripts and Tasklet integration to auto-act on emails—these run autonomously without user initiation. However, evidence is all vendor-sourced with no independent verification of reliability or scope of autonomy. Missing for 10: independent/hands-on confirmation of trigger reliability, detail on trigger configuration UI, and evidence of complex multi-step autonomous workflows beyond simple triggers.
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Shortwave now integrates with Tasklet to take action on your emails automatically. Drafts appear right in Shortwave—not buried in Gmail.”
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [claimed-docs] “connects our AI Assistant to all your business applications, letting you accomplish complex workflows without ever leaving your inbox”
Fastmail's Filters & Rules feature provides server-side automation that runs autonomously in the background without user intervention, and JMAP API tokens plus EventSource/WebPush push notifications allow building custom automated workflows (e.g., an agent reacting to new mail events). However, there is no evidence of purpose-built AI-agent automation tooling, scheduled/triggered agent workflows, or third-party AI automation integrations. Missing for 10: dedicated AI/agent automation framework or examples, evidence of autonomous multi-step workflows beyond simple filters, independent confirmation of using JMAP for agentic background tasks.
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Filters & Rules – Fastmail”
- [claimed-docs] “Get instant push via EventSource — one connection, all mailboxes. Or use WebPush for mobile-compatible push, no permanent connection require…”
- [claimed-docs] “Get instant push via EventSource — one connection, all mailboxes.”
- [claimed-docs] “API tokens”
- [claimed-docs] “API tokens – Fastmail”
- [claimed-docs] “POST a `methodCalls` array. Query, fetch, and send, all in one HTTP request.”
ai-native userDelegate tasks to a built-in AI assistant inside the product
weight 3 · round to ShortwaveShortwave has a built-in AI assistant/executive assistant that can read threads, write drafts, search email history, check calendar, run custom AI filters, and take multi-step actions via triggers and MCP integrations without leaving the inbox — clearly delegatable task execution. Missing for 10: independent hands-on validation of end-to-end delegated task completion (beyond vendor blog claims) and details on reliability/error handling.
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more.”
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
- [claimed-docs] “connects our AI Assistant to all your business applications, letting you accomplish complex workflows without ever leaving your inbox”
- [claimed-docs] “AI Integrations for Shortwave—a powerful new feature that connects our AI Assistant to all your business applications, letting you accomplis…”
- [claimed-docs] “Shortwave now integrates with Tasklet to take action on your emails automatically. Drafts appear right in Shortwave—not buried in Gmail.”
ai-native userOperate the product with natural-language commands
weight 2 · round to ShortwaveShortwave's AI Assistant lets users operate the inbox via natural language—reading threads, writing drafts, searching email history, checking calendar, and running custom AI filters written in plain English—directly in the product's core value proposition. Docs consistently describe this as the primary UX (chat-based assistant, plain-English filter scripts, natural-language triggers). missing for 10: independent/hands-on verification specifically of the natural-language command interface's reliability (community evidence focuses on UI/pricing/privacy, not NL command execution quality).
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more.”
- [claimed-docs] “connects our AI Assistant to all your business applications, letting you accomplish complex workflows without ever leaving your inbox”
- [claimed-docs] “AI Integrations for Shortwave—a powerful new feature that connects our AI Assistant to all your business applications, letting you accomplis…”
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
Fastmailnone0/10No evidence of any natural-language command interface, chat assistant, or NL-to-action layer in Fastmail; the product exposes a structured JMAP API and traditional GUI/keyboard shortcuts, not NL commands. Probes for llms.txt and OpenAPI (which could hint at AI-native tooling) returned 404s, further indicating absence.
- [probe] “PROBE llms.txt: HTTP 404 at https://www.fastmail.help/llms.txt”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.fastmail.help/openapi.json, https://www.fastmail.help/swagger.json, https://www.fastmail…”
- [claimed-docs] “Keyboard shortcuts”
Api quality
ai-native userExplore an interactive API reference with runnable examples
weight 2 · round drawnShortwavenone0/10Shortwave is an email client, not a developer platform with an API reference; probes for llms.txt, docs.md, and OpenAPI specs all returned 404s, and no evidence mentions any interactive API documentation or runnable code examples.
Fastmailnone0/10Fastmail provides JMAP protocol documentation and a developer docs page (fastmail-docs-40), but there is no evidence of an interactive API reference with runnable/try-it-now examples; probes for OpenAPI/Swagger specs and llms.txt both returned 404s (fastmail-probe-1, fastmail-probe-2), indicating no such interactive tooling exists.
- [claimed-docs] “API Documentation”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.fastmail.help/llms.txt”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.fastmail.help/openapi.json, https://www.fastmail.help/swagger.json, https://www.fastmail…”
ai-native userDownload a machine-readable API spec (OpenAPI or equivalent)
weight 2 · round to FastmailShortwavenone0/10Direct probes for OpenAPI/swagger specs and llms.txt all returned 404s, and no docs mention a machine-readable API spec.
Fastmail's JMAP protocol provides a machine-readable session/capabilities discovery endpoint (/.well-known/jmap) and points to formal JMAP specs, plus a general 'API Documentation' page, which partially satisfies the spirit of a machine-readable API description even though it isn't an OpenAPI document. However, direct probes for openapi.json/swagger.json/llms.txt all return 404, showing no actual downloadable OpenAPI-equivalent artifact is published. Missing for 10: an actual downloadable OpenAPI/Swagger/JSON-Schema file, confirmation that fastmail.com/dev/ hosts a structured machine-readable spec rather than prose docs, and independent verification of spec completeness.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “API Documentation”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.fastmail.help/llms.txt”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.fastmail.help/openapi.json, https://www.fastmail.help/swagger.json, https://www.fastmail…”
ai-native userRely on versioned APIs with a documented deprecation policy
weight 2 · round drawnShortwavenone0/10No evidence of any public API, versioning scheme, or deprecation policy; probes for OpenAPI/llms.txt/docs endpoints all returned 404s, and no docs mention versioned APIs.
Fastmailnone0/10Evidence shows Fastmail's JMAP API and documentation (session discovery, OAuth, API tokens, dev docs) but no mention of API versioning scheme or a documented deprecation policy; probes for openapi/llms.txt also 404, suggesting no machine-readable spec exists either.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “API Documentation”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.fastmail.help/llms.txt”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.fastmail.help/openapi.json, https://www.fastmail.help/swagger.json, https://www.fastmail…”
Ai email — stories about ai email in this arenaAi email
Stories about ai email in this arena
Agent workflows
ai-native userAn external agent — Claude, ChatGPT, or my own — can read, triage, draft, and send my email end to end through a documented connection
weight 2 · round to FastmailShortwavenone0/10Shortwave documents an internal AI Assistant that reads/drafts/searches email, and it can act as an MCP *client* connecting its own AI to external apps (Slack, GitHub, Zapier, etc.), but there is no evidence Shortwave exposes itself as an MCP server or documented API that lets an external agent (Claude, ChatGPT, or a custom agent) read/triage/draft/send mail through it. Probes confirm no llms.txt, no docs.md, and no OpenAPI/Swagger endpoint, indicating no documented external-agent connection surface.
- [claimed-docs] “You can connect virtually any application through the Model Context Protocol (MCP). Just click "Add custom integration" and point to an MCP …”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “AI Integrations for Shortwave—a powerful new feature that connects our AI Assistant to all your business applications, letting you accomplis…”
- [claimed-docs] “Connect the AI with your favorite apps and services for enhanced productivity workflows through built-in integrations or MCP”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.shortwave.com/llms.txt”
- [probe] “PROBE docs-md: HTTP 404 at https://www.shortwave.com/docs/.md”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
Fastmail exposes a fully documented JMAP API with OAuth2/Bearer token auth and API tokens (fastmail-docs-1,2,5,38,41) that could let a custom-built agent read, query, and send mail via standard HTTP, satisfying the 'my own agent' case. But there is no evidence of an official MCP server, ChatGPT/Claude connector, or any first-party documented integration enabling Claude or ChatGPT specifically to triage/draft/send end-to-end — probes for llms.txt and OpenAPI discovery both returned 404 (fastmail-probe-1, fastmail-probe-2). Missing for 10: official MCP server or Claude/ChatGPT plugin, documented end-to-end agent workflow (triage+draft+send), and independent evidence of an AI agent actually operating through this API.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement. Works with what you already have.”
- [claimed-docs] “API tokens”
- [claimed-docs] “POST a `methodCalls` array. Query, fetch, and send, all in one HTTP request.”
- [claimed-docs] “Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement.”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.fastmail.help/llms.txt”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.fastmail.help/openapi.json, https://www.fastmail.help/swagger.json, https://www.fastmail…”
Ai assistant
ai-native userAsk an assistant questions across my whole inbox and calendar — who said what, what's outstanding — and get grounded answers
weight 2 · round to ShortwaveDocs directly describe the AI Assistant reading threads, writing drafts, searching entire email history, and checking calendar — matching the grounded cross-inbox/calendar Q&A story. Community evidence corroborates fast search/summaries and real usage, though no independent hands-on confirmation of complex multi-thread grounded reasoning exists. Missing for 10: independent hands-on verification of accuracy/groundedness across large inboxes, and detail on how calendar+email context are combined in answers.
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more.”
- [claimed-docs] “Instant Summaries show up at the very top of your email threads the instant you open them.”
- [community] “'I must say I loved it. In 10min I cleared my inbox which I was postponing for a few weeks... it imported all my aliases and signatures.' Us…”
Fastmailnone0/10There is no evidence of any Fastmail-native AI assistant, chat interface, or grounded Q&A feature over inbox/calendar content; evidence only covers JMAP API access, standard mail features, and general product satisfaction. A third party could build such an assistant using JMAP/API tokens, but no evidence shows Fastmail itself offers this capability.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “API tokens”
- [claimed-docs] “API Documentation”
Ai drafting
ai-native userAI drafts replies in my own voice and tone — ready to review and send, not generic boilerplate
weight 3 · round to ShortwaveShortwave's AI Assistant explicitly 'writes drafts' and Ghostwriter autocompletes replies as you type, confirming AI-drafted replies are a core capability. However, no evidence specifically shows the AI learns or mimics the user's personal voice/tone (vs. generic suggestions or template-based AI Snippets), so the 'own voice' personalization claim is unverified. Missing for 10: explicit documentation of voice/tone personalization or learning from user's writing style, and independent user reports confirming drafts sound authentically like them rather than generic AI text.
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more.”
- [claimed-docs] “you’ll see suggestions presented to you automatically as you draft emails. Just press ‘tab’ to complete.”
- [claimed-docs] “you’ll see suggestions presented to you automatically as you draft emails. Just press ‘tab’ to complete”
- [claimed-docs] “AI Snippets let you define an email template once upfront and then re-use it whenever you need it.”
Ai triage
ai-native userAI triages my inbox for me — auto-labeling, categorizing, and surfacing what needs attention — with behavior I can steer and audit
weight 3 · round to ShortwaveShortwave ships custom AI filters that auto-label, star, and archive using plain-English scripts, plus Bundles/Splits to categorize inbox by importance and one-click identification of important emails/todos, directly matching the triage story; community feedback corroborates the bundling/importance-sorting feature as effective ('top shelf'). Steerability is evidenced via the plain-English filter scripts, but missing for 10: explicit audit-trail/log of AI triage decisions and independent verification of filter reliability at scale.
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Identify important emails & todos with a single click. Sweep away the rest.”
- [claimed-docs] “They’re a simple way to divide your one big inbox into multiple smaller, more focused inboxes – each in its own tab.”
- [claimed-docs] “Splits let you handle different types of emails at different times, so you can stay responsive where it matters most.”
- [community] “Front power-user praised Shortwave's 'Bundles' grouping feature as 'top shelf,' better than Front's tags/folders, though he found Workspaces…”
Fastmailnone0/10Evidence covers Fastmail's rule-based Filters & Rules, search, and JMAP API access, but there is no mention of AI-driven triage, auto-labeling, categorization, or a steerable/auditable AI assistant surfacing important emails. Absence of evidence for this applicable capability means it does not deliver the story.
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Filters & Rules – Fastmail”
- [claimed-docs] “Searching your mail”
Automation depth — how much of the product can run unattendedAutomation depth
How much of the product can run unattended
ai-native userPerform bulk operations across many items at once
weight 2 · round to ShortwaveShortwave's custom AI filters ('automatically label, star, archive, and more with scripts you write in plain English') and one-click sweep of non-important emails/todos (docs-15, docs-29) directly support automated actions applied across many inbox items at once, and triggers (docs-1) extend this to organizing threads into todos in bulk. However, there's no explicit documentation of a true multi-select bulk-action UI, batch limits, or independent hands-on confirmation that these AI filters reliably scale across large volumes of email. Missing for 10: explicit bulk-select/apply workflow docs, scale/performance evidence, and independent user corroboration of bulk automation working as advertised.
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Identify important emails & todos with a single click. Sweep away the rest.”
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
JMAP's design (single HTTP request with a `methodCalls` array for query/fetch/send, fastmail-docs-38) inherently supports batching many operations together, and filters/rules (fastmail-docs-6) allow rule-based bulk processing of mail. However, there's no explicit documentation of a bulk-update/bulk-delete API pattern, no example of bulk operations across large item sets, and no independent evidence of this being used for AI-native bulk workflows. Missing for 10: explicit bulk operation API examples (e.g., bulk delete/move across many message IDs), documented limits/performance for large batches, and independent confirmation of successful bulk automation use.
- [claimed-docs] “POST a `methodCalls` array. Query, fetch, and send, all in one HTTP request.”
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Sync changes more easily, more efficiently, and much, much faster. A single HTTP roundtrip is often all that's required.”
ai-native userDefine rules that trigger actions automatically on events
weight 3 · round to ShortwaveShortwave documents explicit rule/trigger automation: triggers that draft replies when emails arrive, custom AI filters written in plain English that auto-label/star/archive, and Tasklet integration that takes automatic actions on emails as they arrive. This directly matches defining rules that fire on events (email arrival) with automated actions. Missing for 10: independent/hands-on verification that these triggers work reliably in practice, and more detail on rule complexity/limits beyond marketing copy.
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Shortwave now integrates with Tasklet to take action on your emails automatically. Drafts appear right in Shortwave—not buried in Gmail.”
Fastmail's Filters & Rules feature lets users define rule-based automations (e.g., move/tag/forward on incoming mail conditions), which satisfies a basic version of 'rules trigger actions on events.' However, this is a traditional email-filter system, not framed for AI-native/agentic use, and there's no evidence of programmatic rule creation via API/JMAP, webhook-triggered actions, or AI-specific automation hooks beyond generic push/EventSource notifications. Missing for 10: API-driven rule creation/management, AI-agent-specific triggers or actions, and richer automation beyond mail filtering.
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Filters & Rules – Fastmail”
- [claimed-docs] “Get instant push via EventSource — one connection, all mailboxes. Or use WebPush for mobile-compatible push, no permanent connection require…”
- [community] “Fastmail has an easy migration tool as well if you don't want to go the IMAP route. Now, migrating filters and rules over on the other hand.…”
ai-native userSchedule recurring jobs or workflows
weight 2 · round to ShortwaveShortwave offers event-based 'triggers' (auto-draft replies, add comments, organize todos) and custom AI filters that run automatically in plain English, which are a form of automation, but these are reactive triggers on incoming events rather than true time-based recurring/scheduled jobs — the only scheduling feature documented (Scheduled Send) is a one-time future send, not a recurring workflow. Missing for 10: explicit recurring/cron-style scheduling of AI workflows, documentation of periodic digest or repeat-interval automations, and independent confirmation that triggers can run on a time-based recurring cadence rather than only on email arrival.
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Scheduled send gives you the ability to send an email at a future time.”
- [claimed-docs] “Shortwave now integrates with Tasklet to take action on your emails automatically. Drafts appear right in Shortwave—not buried in Gmail.”
Fastmailnone0/10No evidence of scheduling recurring jobs/workflows; only email-specific automation like Filters & Rules, Scheduled Send (one-time), and Snooze are documented, none of which support recurring automated workflows or job scheduling via API/JMAP. missing for 10: recurring job/workflow scheduler, cron-like automation, evidence of JMAP being used to trigger scheduled/recurring tasks.
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Scheduled Send”
- [claimed-docs] “Snooze messages to just when you need them. Whether it’s tickets to that stadium gig in September, or a bill due next Thursday, sometimes yo…”
ai-native userVersion, review, and roll back my automations
weight 1 · round drawnShortwavenone0/10Shortwave offers AI filters, triggers, and MCP integrations for automation, but there is no evidence of version history, review workflows, diffs, or rollback capability for these automations.
Fastmailnone0/10No evidence of any versioning, review, or rollback mechanism for automations (e.g., Filters & Rules history, change logs, or undo for automation configs); Fastmail's docs cover creating filters but nothing about version control or reverting changes.
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Filters & Rules – Fastmail”
Calendar integration — stories about calendar integration in this arenaCalendar integration
Stories about calendar integration in this arena
Calendar
power-userSee my calendar, respond to invites, and create events without leaving the email client
weight 2 · round to FastmailShortwave's AI assistant is documented to 'check your calendar' and integrate with Calendar as one of many connected apps, implying some calendar visibility inside the client, but there is no evidence of responding to invites or creating events without leaving the email client. missing for 10: explicit calendar view/UI, invite RSVP handling, and event-creation workflow evidence.
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more.”
- [claimed-docs] “Connect the AI to your Slack, Calendar, Notion, Asana, Hubspot, and more so you can automate workflows without ever leaving your inbox.”
Fastmail's docs confirm built-in Calendar with event and invitation handling directly in the mail/webmail client (fastmail-docs-14/34), and JMAP supports calendar via CalDAV replacement (fastmail-docs-42), consistent with an integrated calendar app alongside email. However, evidence lacks hands-on/community confirmation of the invite-response and event-creation UX specifically. Missing for 10: independent/community corroboration of calendar RSVP and event-creation workflow, and detail on UI integration depth.
- [claimed-docs] “Calendar events and invitations”
- [claimed-docs] “Calendar events and invitations – Fastmail”
- [claimed-docs] “JMAP is the open protocol that replaces IMAP (and CardDAV and CalDAV). It's faster, simpler, more powerful, and built for how email works to…”
power-userShare my availability or insert bookable meeting times directly into an email
weight 1 · round drawnShortwavenone0/10Evidence shows Shortwave's AI can 'check your calendar' and connect to Calendar via integrations, but there is no mention of sharing availability or inserting bookable meeting time slots into an email — a distinct calendar-scheduling feature not evidenced anywhere in the pack.
Fastmailnone0/10The evidence only shows generic 'Calendar events and invitations' documentation (RSVP/invite handling) with no mention of an availability-sharing or booking-link feature akin to scheduling assistants; no docs or community reports describe inserting bookable meeting slots into emails.
- [claimed-docs] “Calendar events and invitations”
- [claimed-docs] “Calendar events and invitations – Fastmail”
Composing sending — stories about composing sending in this arenaComposing sending
Stories about composing sending in this arena
Sending
power-userSee whether and when recipients opened my email
weight 1 · round drawnShortwavenone0/10No evidence in the pack mentions read receipts, open tracking, or notifications about recipient email opens; Shortwave's documented features cover AI drafting, snippets, scheduling, undo send, and integrations but nothing about tracking whether/when recipients opened a message.
power-userSchedule an email to send later and undo a send within a grace window
weight 2 · round drawnShortwave's docs explicitly describe both scheduled send (set a time, write message, move on) and undo send (revert a sent message back to a draft), directly matching the story. Missing for 10: explicit detail on the undo grace-window duration and independent/hands-on corroboration beyond vendor blog.
- [claimed-docs] “Scheduled send gives you the ability to send an email at a future time.”
- [claimed-docs] “Undo send staves off the panic you feel when you accidentally send a message that wasn't ready by allowing you to revert a sent message back…”
- [claimed-docs] “Scheduled send gives you the ability to send an email at a future time. All you have to do is write a message, set a send time, and then mov…”
Fastmail has dedicated first-party docs for both 'Scheduled Send' and 'Undo send' features, directly matching the story's requirements. Missing for 10: independent/hands-on corroboration of the undo grace-window mechanics or scheduling UX details beyond doc titles.
- [claimed-docs] “Scheduled Send”
- [claimed-docs] “Undo send”
- [claimed-docs] “Scheduled Send – Fastmail”
- [claimed-docs] “Undo send – Fastmail”
Templates
power-userInsert saved snippets or templates — with variables and attachments — instead of retyping the same reply
weight 2 · round to ShortwaveShortwave documents 'AI Snippets' that let users define an email template once and reuse it, available for individual and team use — directly matching the core snippet/template story. However, the evidence never confirms support for variables (dynamic fields) within snippets or attaching files as part of a snippet, both explicitly requested in the story. Missing for 10: documentation of variable/placeholder support in snippets, documentation of attachment bundling with snippets, and independent/hands-on confirmation of the feature working as described.
- [claimed-docs] “AI Snippets let you define an email template once upfront and then re-use it whenever you need it.”
- [claimed-docs] “AI Snippets are available both for individual use and for use across your team.”
Fastmail documents a dedicated "Templates" feature for saved replies, supporting the core ask of inserting canned text instead of retyping, but the evidence pack gives only the article title with no detail on variable substitution or attachment inclusion. missing for 10: documentation confirming template variables (e.g. name/date placeholders), attachment support within templates, and any independent/hands-on confirmation of these specifics.
- [claimed-docs] “Templates”
- [claimed-docs] “Templates – Fastmail”
Offline reliability — stories about offline reliability in this arenaOffline reliability
Stories about offline reliability in this arena
Offline
power-userRead, search, and write email offline, with changes syncing when I reconnect
weight 2 · round to FastmailThe founder states Gmail API integration enables 'offline handling' alongside real-time sync, implying some offline capability, but there's no detail on offline search, offline composing, or how changes reconcile on reconnect. missing for 10: documentation of offline read/search functionality, offline draft writing, and sync-conflict resolution behavior.
- [community] “Founder: We integrate with Gmail's APIs (not IMAP) to enable faster real-time updates, better latency compensation, offline handling, bundle…”
Fastmail has a dedicated 'Offline support' help article and a documented behavior detail (snoozed messages only reappear once back online, implying local caching + resync), which supports reading/writing offline with sync on reconnect. However, the evidence pack only gives titles/snippets, not confirmation that full-text search works offline or exactly how conflict resolution/sync works, and there's no independent hands-on test confirming offline compose/search reliability. Missing for 10: detailed doc content on offline search, independent verification of offline write/compose queuing and reconnection sync behavior, and confirmation across web/mobile clients.
- [claimed-docs] “Offline support”
- [claimed-docs] “Offline support – Fastmail”
- [claimed-docs] “If you're offline when a snoozed message is scheduled to return to your Inbox, you will not see the snoozed message reappear until you're ba…”
- [claimed-docs] “Sync changes more easily, more efficiently, and much, much faster. A single HTTP roundtrip is often all that's required.”
Openness — open source, data portability, and self-hosting storiesOpenness
Open source, data portability, and self-hosting stories
ai-native userDo everything through the API that I can do in the UI
weight 2 · round to FastmailShortwavenone0/10No evidence of a public API for Shortwave; probes for llms.txt, docs-md, and OpenAPI specs all returned 404, and no documentation mentions programmatic access to core features like AI assistant, triggers, or inbox management outside the UI/MCP integration (which is inbound, not an outbound API for replicating UI actions).
Fastmail's JMAP API is well-documented for core mail operations (session discovery, OAuth, push via EventSource, single-roundtrip method calls) and JMAP also natively covers contacts/calendar, giving broad coverage beyond typical webmail APIs. However, the evidence never confirms API parity for many UI-only features referenced in docs (masked email management, snooze, templates, filters/rules configuration, scheduled send) — these are documented as UI/help features without corresponding API examples. missing for 10: explicit API endpoints/examples for masked email, snooze, filters, templates, scheduled send parity; independent developer confirmation that all UI actions are API-reachable.
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “Sync changes more easily, more efficiently, and much, much faster. A single HTTP roundtrip is often all that's required.”
- [claimed-docs] “POST a `methodCalls` array. Query, fetch, and send, all in one HTTP request.”
- [claimed-docs] “API Documentation”
- [claimed-docs] “Masked Email”
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Snooze messages to just when you need them. Whether it’s tickets to that stadium gig in September, or a bill due next Thursday, sometimes yo…”
ai-native userExport all of my data in open formats and leave
weight 3 · round to FastmailShortwavenone0/10No evidence of any data export feature (mailbox, comments, snippets, etc.) in open formats; probes for llms.txt, docs-md, and openapi endpoints all returned 404, and no changelog/blog mentions an export or account-portability capability. Community threads mention deleting the account making it 'low-risk' to switch back to Gmail, but that is because Shortwave uses Gmail as the underlying store, not because Shortwave itself offers a data export mechanism. missing for 10: any documented export/download feature, supported open file formats, or migration/backup tooling.
- [probe] “PROBE llms.txt: HTTP 404 at https://www.shortwave.com/llms.txt”
- [probe] “PROBE docs-md: HTTP 404 at https://www.shortwave.com/docs/.md”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
- [community] “'I must say I loved it. In 10min I cleared my inbox which I was postponing for a few weeks... it imported all my aliases and signatures.' Us…”
Fastmail's evidence shows JMAP is an open, non-proprietary standard with full API access (session object, method calls, OAuth tokens) that could in principle be used to pull out all mail data, and there's a dedicated 'Open source and standards' page, but there is no explicit documentation of a one-click full data export/backup feature (mail+contacts+calendar) for leaving the service — only 'Import your mail' guidance is evidenced. missing for 10: documented full-account export/backup tool covering mail, contacts, and calendar; explicit data-portability/GDPR export docs; independent confirmation of successful full export.
- [claimed-docs] “JMAP is an open standard any organisation can implement, not more proprietary lock-in from big tech companies.”
- [claimed-docs] “Open source and standards | Fastmail”
- [claimed-docs] “Fetch `/.well-known/jmap` for the session object - capabilities, accounts, and all API URLs.”
- [claimed-docs] “API Documentation”
- [claimed-docs] “Import your mail”
ai-native userRead the product's source under an open license
weight 2 · round drawnShortwavenone0/10No evidence of any open-source license or public source repository for Shortwave; it is a closed commercial SaaS email client with no mention of open licensing anywhere in the evidence pack.
Fastmailnone0/10Fastmail is a proprietary commercial email service; while it supports open standards like JMAP and has a page titled 'Open source and standards' (fastmail-docs-23), there is no evidence that Fastmail's own product source code is published under an open license for users/AI agents to read.
- [claimed-docs] “Open source and standards | Fastmail”
- [claimed-docs] “JMAP is an open standard any organisation can implement, not more proprietary lock-in from big tech companies.”
ai-native userSelf-host the core product
weight 3 · round drawnShortwavenone0/10Shortwave is a hosted SaaS email client with no evidence of any self-hostable version; it relies on Google servers and its own cloud infrastructure (comm-11), and no self-hosting docs, Docker images, or open-source releases exist in the evidence pack.
- [community] “Security-focused user: 'there is no way I could use a web mail client for security reasons (as a security consultant, we use PGP a lot and n…”
- [probe] “PROBE llms.txt: HTTP 404 at https://www.shortwave.com/llms.txt”
- [probe] “PROBE docs-md: HTTP 404 at https://www.shortwave.com/docs/.md”
- [probe] “PROBE openapi: all candidate paths 404 (https://www.shortwave.com/openapi.json, https://www.shortwave.com/swagger.json, https://www.shortwav…”
Privacy posture — data-handling and privacy storiesPrivacy posture
Data-handling and privacy stories
ai-native userChoose where my data is stored (region/residency)
weight 2 · round drawnShortwavenone0/10No evidence anywhere in the pack mentions data residency, region selection, or storage location controls; Shortwave is shown to run on Google servers with no configurable region options, and community comments only raise general privacy/security concerns without any residency feature being offered.
- [community] “Security-focused user: 'there is no way I could use a web mail client for security reasons (as a security consultant, we use PGP a lot and n…”
- [community] “User quoted privacy policy allowing sharing of email content/metadata with third-party vendors and said 'Hard pass' given business email con…”
Fastmailnone0/10The evidence pack contains no mention of data residency, regional storage options, or where Fastmail's servers/data centers are located; nothing addresses letting users choose a storage region. missing for 10: any documentation of regional data residency options, data center locations, or user controls for choosing where data is stored.
ai-native userPrevent my data from being used to train AI models
weight 3 · round drawnShortwavenone0/10No evidence pack item describes any setting, policy statement, or opt-out mechanism letting users prevent their email/AI data from being used for model training; the only related community evidence (shortwave-comm-7) actually flags that Shortwave's privacy policy permits sharing email content/metadata with third-party vendors, which a user rejected outright rather than confirming a training opt-out exists.
- [community] “User quoted privacy policy allowing sharing of email content/metadata with third-party vendors and said 'Hard pass' given business email con…”
- [community] “Privacy concern: user worried about syncing sensitive emails (OTPs, bank/SSN emails) to Shortwave's servers and wished for a denylist to exc…”
Fastmailnone0/10No evidence in the pack addresses AI training data usage, opt-out controls, or any explicit privacy commitment regarding AI model training on user email data. missing for 10: any AI-training data policy, opt-out mechanism, or explicit statement that user data is not used to train AI models.
ai-native userControl data retention and deletion
weight 2 · round to ShortwaveThe only evidence touching on data deletion is a community anecdote that deleting one's Shortwave account makes it low-risk to switch back to Gmail, implying account-level deletion works, but there is no documented retention policy, granular deletion controls, or data-lifecycle settings; community comments even flag privacy concerns about email content being synced/shared with third-party vendors with no denylist option. missing for 10: documented retention policy, explicit deletion/export controls, first-party privacy/data-handling documentation.
- [community] “'I must say I loved it. In 10min I cleared my inbox which I was postponing for a few weeks... it imported all my aliases and signatures.' Us…”
- [community] “Privacy concern: user worried about syncing sensitive emails (OTPs, bank/SSN emails) to Shortwave's servers and wished for a denylist to exc…”
- [community] “User quoted privacy policy allowing sharing of email content/metadata with third-party vendors and said 'Hard pass' given business email con…”
ai-native userOpt out of telemetry and usage tracking
weight 2 · round drawnShortwavenone0/10No evidence Shortwave offers any telemetry/usage-tracking opt-out control; documentation focuses on AI features and integrations, and community discussion instead raises concerns about email content being shared with third-party vendors with no denylist option, but nothing addresses telemetry/analytics opt-out specifically.
- [community] “Privacy concern: user worried about syncing sensitive emails (OTPs, bank/SSN emails) to Shortwave's servers and wished for a denylist to exc…”
- [community] “User quoted privacy policy allowing sharing of email content/metadata with third-party vendors and said 'Hard pass' given business email con…”
Privacy tracking — stories about privacy tracking in this arenaPrivacy tracking
Stories about privacy tracking in this arena
Protection
switcherUse aliases or masked addresses so sign-ups and strangers never learn my real address
weight 1 · round to FastmailShortwavenone0/10No evidence Shortwave offers email aliasing, masked addresses, or similar identity-protection features for sign-ups; the pack only covers AI assistant, integrations, and inbox management features unrelated to address masking.
Fastmail's Masked Email feature (fastmail-docs-18/29) directly delivers per-signup masked addresses so real address stays hidden, plus separate alias setup docs (fastmail-docs-12/36), and community testimony confirms real-world use for throwaway/sketchy sites (fastmail-comm-1). missing for 10: independent hands-on verification of masked-email creation flow beyond docs and a single community mention, and no detail on limits/edge cases of masked addresses.
- [claimed-docs] “Masked Email”
- [claimed-docs] “Masked Email – Fastmail”
- [claimed-docs] “How to set up aliases”
- [claimed-docs] “How to set up aliases – Fastmail”
- [community] “Fastmail is fantastic, I've been a very happy customer for at least a couple years now. Masked emails have been so nice for throwaway/sketch…”
switcherThe client protects me from senders' tracking — blocking read pixels by default — and is transparent about what it does with my mail data
weight 2 · round drawnShortwavenone0/10No evidence anywhere in the pack describes Shortwave blocking sender tracking pixels, nor does it detail transparent data-handling practices for mail content; the only related community evidence (comm-6, comm-7) actually raises unaddressed privacy concerns about syncing sensitive mail and sharing content/metadata with third-party vendors. missing for 10: any mention of read-pixel/tracking-pixel blocking, any transparency documentation on mail data handling, and evidence rebutting the third-party data-sharing concerns.
- [community] “Privacy concern: user worried about syncing sensitive emails (OTPs, bank/SSN emails) to Shortwave's servers and wished for a denylist to exc…”
- [community] “User quoted privacy policy allowing sharing of email content/metadata with third-party vendors and said 'Hard pass' given business email con…”
Search history — stories about search history in this arenaSearch history
Stories about search history in this arena
Migration
switcherImport my complete mail history and contacts from my old provider or client
weight 1 · round to FastmailShortwave is built directly on Gmail's APIs, so it can pull in an existing Gmail account's aliases and signatures (one user reported it 'imported all my aliases and signatures' during onboarding), but this is only a Gmail-to-Shortwave migration, not import from another provider/client like Outlook or Yahoo — a security-focused user explicitly noted 'it only works with Google servers.' Additionally, a documented free-plan limitation caps historical search import at 90 days, undercutting 'complete mail history.' Missing for 10: evidence of contacts import, support for non-Gmail providers, and confirmation that paid plans truly import full history without gaps.
- [community] “'I must say I loved it. In 10min I cleared my inbox which I was postponing for a few weeks... it imported all my aliases and signatures.' Us…”
- [community] “Free plan limitation noted: emails from more than 90 days before signup aren't imported for search, and snoozed emails past that window won'…”
- [community] “Security-focused user: 'there is no way I could use a web mail client for security reasons (as a security consultant, we use PGP a lot and n…”
- [community] “User complaint: 'all these apps either want gmail way too many gmail permissions, and/or are hosted... I'm trying to get rid of gmail lol.'”
Fastmail has a documented 'Import your mail' tool plus IMAP fetch/forwarding options for migrating mail from other providers, and community reports confirm an easy migration tool and IMAP-based fetching from Gmail. However, evidence does not clearly cover contacts import, and community feedback flags that filters/rules migration is notably harder ('migrating filters and rules over on the other hand...'). Missing for 10: explicit contacts-import documentation, confirmation of complete mail history fidelity, and stronger independent verification of a smooth full-history+contacts migration.
- [claimed-docs] “Import your mail”
- [claimed-docs] “Import your mail – Fastmail”
- [community] “As an alternative to forwarding, you can also configure Fastmail to fetch mail from (and send via) Gmail like a mail client.”
- [community] “Fastmail has an easy migration tool as well if you don't want to go the IMAP route. Now, migrating filters and rules over on the other hand.…”
- [claimed-docs] “Move from Gmail”
Search
power-userSearch is fast and precise — operators, filters, and ranked results across my full mail history
weight 2 · round to FastmailShortwavedisputedcontradicted4/10Shortwave's AI assistant is documented to 'search your entire email history' (shortwave-docs-12/28), but community evidence shows the free plan doesn't import emails older than 90 days before signup for search, contradicting the 'full mail history' claim, and no evidence describes search operators, advanced filters, or ranked-result mechanics. Missing for 10: documented search operators/filters syntax, ranking algorithm details, confirmation that paid tiers truly cover unlimited history without caveats.
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more”
- [claimed-docs] “it can read threads, write drafts, search your entire email history, check your calendar, and more.”
- [community] “Free plan limitation noted: emails from more than 90 days before signup aren't imported for search, and snoozed emails past that window won'…”
Fastmail has a dedicated 'Searching your mail' help article confirming search is a first-class feature, and JMAP's fast query/fetch model implies backend efficiency, but the evidence pack never details actual search operators, filter syntax, ranking behavior, or performance across full mail history. missing for 10: documented search operator syntax (from:, subject:, has:attachment etc.), evidence of ranked/relevance-based results, benchmarks or user reports on search speed across large mail archives, independent corroboration of search precision.
- [claimed-docs] “Searching your mail”
- [claimed-docs] “Searching your mail – Fastmail”
- [claimed-docs] “Sync changes more easily, more efficiently, and much, much faster. A single HTTP roundtrip is often all that's required.”
- [claimed-docs] “POST a `methodCalls` array. Query, fetch, and send, all in one HTTP request.”
Speed keyboard — stories about speed keyboard in this arenaSpeed keyboard
Stories about speed keyboard in this arena
Shortcuts
power-userDo everything from the keyboard — comprehensive shortcuts and a command palette — in an interface fast enough to never make me wait
weight 3 · round to FastmailShortwavenone0/10The evidence pack contains no mentions of keyboard shortcuts, a command palette, or performance/speed benchmarks — all citations focus on AI features, integrations, and collaboration tools. Absence of evidence for this applicable axis (email clients commonly tout keyboard-driven UX, e.g. Superhuman comparisons appear in community items) yields 'none' rather than 'na'.
Fastmail documents a dedicated keyboard shortcuts feature and JMAP-based sync architecture emphasizing speed, and community feedback corroborates the interface being notably fast ('a ton faster' than alternatives). However, there is no evidence of a command palette or comprehensive shortcut coverage claims, and no hands-on confirmation of full keyboard-only operation. Missing for 10: explicit command-palette feature, evidence of exhaustive/comprehensive shortcut coverage beyond a single help article, independent benchmarking of UI responsiveness under load.
- [claimed-docs] “Keyboard shortcuts”
- [claimed-docs] “Keyboard shortcuts – Fastmail”
- [claimed-docs] “Sync changes more easily, more efficiently, and much, much faster. A single HTTP roundtrip is often all that's required.”
- [community] “I switched from protonmail to fastmail recently. Fastmail was a ton faster and didn't randomly forget my sessions. Night and day to use. It …”
- [community] “I recently moved my email to FastMail and I really like it. I even prefer its web interface over Gmail's.”
Team collaboration — stories about team collaboration in this arenaTeam collaboration
Stories about team collaboration in this arena
Channels
team-leadThe same inbox also handles adjacent customer channels — SMS, WhatsApp, social, or live chat — beside email
weight 1 · round drawnShortwavenone0/10The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)
Routing
team-leadAssign conversations to teammates and route incoming mail with rules so ownership is explicit
weight 2 · round drawnShortwave offers team comments and @mention to loop teammates into a thread (giving them access to the email) and custom AI filters that can label/archive/star via plain-English rules, but there is no evidence of an explicit 'assign conversation to teammate' ownership feature or rule-based routing of incoming mail to specific team members/inboxes. missing for 10: explicit conversation assignment/ownership feature, mail routing rules tied to teammates, evidence of shared/team inbox queue management.
- [claimed-docs] “Team comments let you privately discuss an email with your team directly in Shortwave, so you can plan how to respond together”
- [claimed-docs] “Something special happens when you `@mention` a teammate in a comment – they suddenly get access to not just your comment, but the email too”
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [community] “Front power-user praised Shortwave's 'Bundles' grouping feature as 'top shelf,' better than Front's tags/folders, though he found Workspaces…”
Fastmail's docs confirm mail routing via Filters & Rules, which lets a team-lead direct incoming mail to specific folders/addresses, but there is no evidence of any conversation-assignment feature (assigning a thread to a specific teammate with ownership tracking) anywhere in the pack. Missing for 10: conversation/ticket assignment to teammates, ownership/status indicators, any shared-inbox collaboration UI beyond basic filters.
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Filters & Rules – Fastmail”
Shared inbox
team-leadWe can discuss an email in an internal side-thread — comments and @mentions beside the message — instead of forwarding copies around
weight 2 · round to ShortwaveShortwave's Team Comments feature explicitly lets teammates privately discuss an email in-app rather than forwarding, with @mentions that grant the mentioned teammate access to the comment and the email — directly matching the story. Missing for 10: independent/hands-on corroboration of the comment-thread UX beyond vendor blog posts, and detail on comment threading/notification mechanics.
- [claimed-docs] “Team comments let you privately discuss an email with your team directly in Shortwave, so you can plan how to respond together”
- [claimed-docs] “Something special happens when you `@mention` a teammate in a comment – they suddenly get access to not just your comment, but the email too”
- [claimed-docs] “Team comments let you privately discuss an email with your team directly in Shortwave”
- [claimed-docs] “Something special happens when you @mention a teammate in a comment – they suddenly get access to not just your comment, but the email too”
- [claimed-docs] “Set up triggers to draft replies when emails arrive, add comments for your team, organize threads into todos, and connect to 3,000+ other ap…”
team-leadMy team works shared inboxes together — shared accounts or team channels where everyone sees the same conversation state
weight 3 · round to ShortwaveShortwave offers team comments and @mention that grant teammates access to specific emails/threads (shortwave-docs-10,11,34,37), enabling some shared visibility and discussion. However, community evidence explicitly questions whether Shortwave's 'Bundles'/Workspaces model can replace true shared/team inboxes as found in dedicated tools (shortwave-comm-4), and there is no direct documentation of a shared-account or team-channel inbox where the whole team sees identical conversation state by default. Missing for 10: explicit shared-inbox/team-channel product feature, documentation of multi-user access to a single mailbox, and confirmation that collaboration extends beyond per-email comments to full inbox-level shared state.
- [claimed-docs] “Team comments let you privately discuss an email with your team directly in Shortwave, so you can plan how to respond together”
- [claimed-docs] “Something special happens when you `@mention` a teammate in a comment – they suddenly get access to not just your comment, but the email too”
- [claimed-docs] “Something special happens when you @mention a teammate in a comment – they suddenly get access to not just your comment, but the email too”
- [claimed-docs] “Team comments let you privately discuss an email with your team directly in Shortwave”
- [community] “Front power-user praised Shortwave's 'Bundles' grouping feature as 'top shelf,' better than Front's tags/folders, though he found Workspaces…”
Fastmailnone0/10Evidence covers JMAP protocol, personal productivity features, and multi-account login, but there is no mention of shared inboxes, team channels, or shared conversation state features for teams. Fastmail's docs reference 'Logging in to multiple accounts' which is about one user accessing several separate accounts, not shared team visibility into the same inbox.
- [claimed-docs] “Logging in to multiple accounts”
- [claimed-docs] “Logging in to multiple accounts – Fastmail”
Triage inbox — stories about triage inbox in this arenaTriage inbox
Stories about triage inbox in this arena
Followups
power-userSnooze conversations and set follow-up reminders that resurface a thread if nobody replies
weight 2 · round to FastmailCommunity evidence confirms Shortwave has a snooze feature (comm-10 references 'snoozed emails' behavior), implying threads can be snoozed and resurfaced, but no evidence describes a follow-up reminder that resurfaces a thread specifically when nobody replies. Missing for 10: dedicated docs on follow-up/no-reply reminders, evidence of reminder triggers tied to reply detection, and confirmation of default snooze durations or scheduling UI for this specific workflow.
- [community] “Free plan limitation noted: emails from more than 90 days before signup aren't imported for search, and snoozed emails past that window won'…”
Fastmail's docs confirm a snooze feature that resurfaces messages at a chosen time, including behavior when offline, which covers the 'snooze conversations' half of the story. However there is no evidence of a 'nudge'/follow-up reminder that resurfaces a thread specifically if nobody replies — snoozing is time-based, not reply-tracking. missing for 10: evidence of a no-reply-triggered follow-up reminder feature, independent confirmation of snooze behavior beyond the offline-support note.
- [claimed-docs] “Snooze messages to just when you need them. Whether it’s tickets to that stadium gig in September, or a bill due next Thursday, sometimes yo…”
- [claimed-docs] “If you're offline when a snoozed message is scheduled to return to your Inbox, you will not see the snoozed message reappear until you're ba…”
Inbox structure
power-userSelect many conversations at once and archive, label, or mark them done in one stroke
weight 1 · round to ShortwaveShortwave's docs mention bulk-oriented behaviors—custom AI filters that automatically label/star/archive matching emails, and a one-click 'sweep away the rest' declutter action—that imply multi-conversation bulk actions, but there is no explicit mention of manually multi-selecting conversations and applying archive/label/mark-done in one stroke. Missing for 10: explicit multi-select UI documentation, confirmation that labels/archive/done can be applied simultaneously to a manual selection, and independent/hands-on confirmation of this specific workflow.
- [claimed-docs] “Take control of your inbox with custom AI filters. Automatically label, star, archive, and more with scripts you write in plain English.”
- [claimed-docs] “Identify important emails & todos with a single click. Sweep away the rest.”
Fastmail's documented Keyboard Shortcuts and Filters & Rules pages imply an interface that supports quick, multi-message actions, but no citation explicitly describes selecting multiple conversations for bulk archive/label/mark-done in one action. missing for 10: explicit documentation or hands-on evidence of multi-select checkboxes, bulk archive/label/mark-done actions, and confirmation of conversation-view group actions.
- [claimed-docs] “Keyboard shortcuts”
- [claimed-docs] “Keyboard shortcuts – Fastmail”
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Filters & Rules – Fastmail”
power-userSplit my inbox into focused streams — important, team, newsletters, calendar invites — so triage happens in priority order, not arrival order
weight 3 · round to ShortwaveShortwave's 'Splits' feature explicitly lets users divide one inbox into multiple focused inboxes by importance/type, each in its own tab, directly matching the triage-by-priority story, and independent community feedback (Front power-user) praised the related 'Bundles' grouping as 'top shelf.' Missing for 10: explicit documentation that the default splits match the exact categories named (team, newsletters, calendar invites) rather than just importance-based tabs, and more independent verification of the feature's real-world triage benefit.
- [claimed-docs] “They’re a simple way to divide your one big inbox into multiple smaller, more focused inboxes – each in its own tab.”
- [claimed-docs] “They're a simple way to divide your one big inbox into multiple smaller, more focused inboxes – each in its own tab.”
- [claimed-docs] “Splits let you handle different types of emails at different times, so you can stay responsive where it matters most.”
- [community] “Front power-user praised Shortwave's 'Bundles' grouping feature as 'top shelf,' better than Front's tags/folders, though he found Workspaces…”
Fastmail's Filters & Rules can route mail (e.g. newsletters, calendar invites) into separate folders/labels, and saved searches let a power-user build custom views, giving a rough approximation of prioritized streams — but the evidence never shows a dedicated multi-pane/tabbed 'focused inbox' UI or explicit stream-based triage ordering like Gmail's Priority Inbox or Outlook's Focused Inbox. missing for 10: a documented feature for simultaneous multi-stream inbox views, automatic 'important' classification, and evidence of ordering triage by priority rather than by folder/search separately.
- [claimed-docs] “Filters & Rules”
- [claimed-docs] “Filters & Rules – Fastmail”
- [claimed-docs] “Searching your mail”
- [claimed-docs] “Searching your mail – Fastmail”
- [claimed-docs] “Calendar events and invitations”
- [claimed-docs] “Calendar events and invitations – Fastmail”
Not comparable on these axes
ai-native userUse an official CLI
weight 2 · not comparableShortwaven/aShortwave is an AI email client product, not a developer tool/platform where an official CLI is a natural offering; no evidence suggests it ships or intends a CLI, and the product's interaction model is web/app-based with MCP integrations rather than command-line workflows.
ai-native userTest against a sandbox environment without touching production data
weight 1 · not comparableShortwaven/aShortwave is an AI-native email client, not a developer platform or API product; there is no concept of a sandbox vs. production environment for testing in this context, so this axis is a category error for this product type.