Email Clients & Email AI arenaEmail Clients & Email AI
Email clients and AI-native email apps — the inbox war refought in the AI era — judged on triage and split inboxes, snippets and templates, shared team inboxes, calendar integration, search, keyboard-first speed, offline resilience, multi-account and open-protocol portability, tracking protection, and how completely an AI agent can read, triage, draft, and send through documented APIs and MCP servers. Transactional email APIs, email marketing, and help-desk ticketing are separate arenas; Missive is judged here as the shared-inbox anchor and Fastmail as the classic open-protocol anchor. Notion Mail was evaluated and excluded: Notion's own help center announces the Notion Mail inbox shuts down on September 22, 2026.
54 user stories · 324 judged cells · updated 2026-09-16 · Evidence as of 2026-09-16
Leaderboard — every product ranked by evidenceLeaderboard
Rank by
| 1 |  AgentMailfree-tier vs Zero ↗ | 82/100 | 33/100 | 34/100 | 25/100 | 28/100 | npm 105.4k/wkpypi 294.1k/wk | 12/19 verified | 44/100 integrity | ||
| 2 |  Zerofree-tier vs AgentMail ↗ | 29/100 | 58/100 | untested | 47/100 | 9/100 | ★ 10.8k▲ 6.7k/yr | 19/25 verified · 2 disputed | 45/100 integrity | ||
| 3 |  Missivefree-tier vs AgentMail ↗ | 43/100 | 55/100 | 0/100 | 5/100 | 16/100 | 7/28 verified | 29/100 integrity | |||
| 4 |  Superhuman Mailsubscription-per-seat vs AgentMail ↗ | 17/100 | 72/100 | 0/100 | 6/100 | 43/100 | 6/28 verified · 2 disputed | 0/100 integrity | |||
| 5 |  Shortwavefree-tier vs AgentMail ↗ | 13/100 | 78/100 | 0/100 | 0/100 | 41/100 | 10/24 verified · 1 disputed | 17/100 integrity | |||
| 6 |  Fastmailsubscription-per-seat vs AgentMail ↗ | 21/100 | 7/100 | 7/100 | 13/100 | 19/100 | 10/25 verified | 47/100 integrity |
Best by user type — persona-weighted winnersBest by user type
Per persona, the product with the highest persona-weighted coverage over just that persona's stories — not the same ranking as the overall PA Score leaderboard above.
Story matrix — every product × every judged storyStory matrix
54/54 stories shown · legend
Accounts openness — stories about accounts openness in this arenaAccounts openness
Multi account
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Accounts openness — stories about accounts openness in this arenaConnect several accounts across providers — Gmail, Microsoft 365, IMAP — and work them from one place | switcher | partialC 6/10 | none 0/10 | partialC 4/10 | disputedD 4/10 | partialX 6/10 | n/a |
Portability
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Accounts openness — stories about accounts openness in this arenaMy mail stays reachable over open protocols and standard formats — IMAP/JMAP/SMTP access and standards-based export — so no client can lock me in | switcher | none 0/10 | none 0/10 | none 0/10 | none 0/10 | fullX 8/10 | partialC 6/10 |
| Accounts openness — stories about accounts openness in this arenaSelf-host the email app and keep the mail pipeline under my own control | switcher | none 0/10 | none 0/10 | none 0/10 | fullT 7/10 | none 0/10 | none 0/10 |
Agenticness — how well agents can access and operate the productAgenticness
Agent access
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Agenticness — how well agents can access and operate the productPoint an agent at llms.txt or agent-oriented docs | ai-native | none 0/10 | none 0/10 | none 0/10 | partialT 6/10 | none 0/10 | fullT 9/10 |
| Agenticness — how well agents can access and operate the productRun the product headlessly / in CI for automation | ai-native | none 0/10 | none 0/10 | partialT 3/10 | none 0/10 | partialX 5/10 | fullT 7/10 |
| Agenticness — how well agents can access and operate the productPlug MCP servers into this product so it can use their tools | ai-native | none 0/10 | fullX 8/10 | fullC 8/10 | none 0/10 | none 0/10 | n/a |
| Agenticness — how well agents can access and operate the productConnect an agent via an official MCP server | ai-native | fullT 8/10 | none 0/10 | fullT 9/10 | fullT 8/10 | none 0/10 | fullT 8/10 |
| Agenticness — how well agents can access and operate the productUse an official CLI | ai-native | none 0/10 | n/a | none 0/10 | none 0/10 | none 0/10 | fullT 7/10 |
| Agenticness — how well agents can access and operate the productDrive the product through a documented public API | ai-native | partialT 6/10 | none 0/10 | fullT 8/10 | fullT 8/10 | fullC 8/10 | fullT 9/10 |
| Agenticness — how well agents can access and operate the productIssue scoped/least-privilege API credentials for an agent | ai-native | none 0/10 | none 0/10 | partialC 5/10 | none 0/10 | partialX 6/10 | fullC 8/10 |
| Agenticness — how well agents can access and operate the productBuild against official SDKs | ai-native | none 0/10 | none 0/10 | none 0/10 | partialT 5/10 | none 0/10 | fullT 8/10 |
| Agenticness — how well agents can access and operate the productSubscribe to events via webhooks | ai-native | none 0/10 | none 0/10 | partialC 4/10 | none 0/10 | partialC 5/10 | fullC 9/10 |
Agentic features
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Agenticness — how well agents can access and operate the productGet AI-generated insights and suggestions from my data inside the product | ai-native | fullC 9/10 | fullC 8/10 | partialC 5/10 | fullT 7/10 | none 0/10 | n/a |
| Agenticness — how well agents can access and operate the productSet up automations that run autonomously in the background | ai-native | partialC 6/10 | fullC 7/10 | partialC 7/10 | none 0/10 | partialC 5/10 | partialC 5/10 |
| Agenticness — how well agents can access and operate the productDelegate tasks to a built-in AI assistant inside the product | ai-native | fullC 8/10 | fullC 8/10 | fullC 7/10 | fullT 8/10 | none 0/10 | n/a |
| Agenticness — how well agents can access and operate the productOperate the product with natural-language commands | ai-native | fullT 8/10 | fullC 8/10 | fullC 7/10 | fullX 7/10 | none 0/10 | partialT 6/10 |
Api quality
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Agenticness — how well agents can access and operate the productExplore an interactive API reference with runnable examples | ai-native | none 0/10 | none 0/10 | none 0/10 | none 0/10 | none 0/10 | partialT 5/10 |
| Agenticness — how well agents can access and operate the productDownload a machine-readable API spec (OpenAPI or equivalent) | ai-native | none 0/10 | none 0/10 | none 0/10 | none 0/10 | partialT 4/10 | fullT 9/10 |
| Agenticness — how well agents can access and operate the productTest against a sandbox environment without touching production data | ai-native | none 0/10 | n/a | none 0/10 | none 0/10 | none 0/10 | none 0/10 |
| Agenticness — how well agents can access and operate the productRely on versioned APIs with a documented deprecation policy | ai-native | none 0/10 | none 0/10 | none 0/10 | none 0/10 | none 0/10 | none 0/10 |
Ai email — stories about ai email in this arenaAi email
Agent workflows
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Ai email — stories about ai email in this arenaAn external agent — Claude, ChatGPT, or my own — can read, triage, draft, and send my email end to end through a documented connection | ai-native | fullT 8/10 | none 0/10 | partialT 6/10 | fullT 8/10 | partialT 5/10 | fullT 8/10 |
Ai assistant
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Ai email — stories about ai email in this arenaAsk an assistant questions across my whole inbox and calendar — who said what, what's outstanding — and get grounded answers | ai-native | fullC 8/10 | fullX 8/10 | partialC 6/10 | partialT 6/10 | none 0/10 | none 0/10 |
Ai drafting
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Ai email — stories about ai email in this arenaAI drafts replies in my own voice and tone — ready to review and send, not generic boilerplate | ai-native | fullC 9/10 | partialC 6/10 | partialC 4/10 | partialX 5/10 | none 0/10 | none 0/10 |
Ai triage
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Ai email — stories about ai email in this arenaAI triages my inbox for me — auto-labeling, categorizing, and surfacing what needs attention — with behavior I can steer and audit | ai-native | fullC 8/10 | fullX 7/10 | partialC 6/10 | partialT 6/10 | none 0/10 | none 0/10 |
Automation depth — how much of the product can run unattendedAutomation depth
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Automation depth — how much of the product can run unattendedPerform bulk operations across many items at once | ai-native | partialC 6/10 | partialC 6/10 | partialC 3/10 | partialT 5/10 | partialC 5/10 | partialC 4/10 |
| Automation depth — how much of the product can run unattendedDefine rules that trigger actions automatically on events | ai-native | fullC 7/10 | fullC 7/10 | partialC 5/10 | none 0/10 | partialX 5/10 | partialC 5/10 |
| Automation depth — how much of the product can run unattendedSchedule recurring jobs or workflows | ai-native | partialC 5/10 | partialC 4/10 | none 0/10 | none 0/10 | none 0/10 | n/a |
| Automation depth — how much of the product can run unattendedVersion, review, and roll back my automations | ai-native | none 0/10 | none 0/10 | none 0/10 | n/a | none 0/10 | n/a |
Calendar integration — stories about calendar integration in this arenaCalendar integration
Calendar
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Calendar integration — stories about calendar integration in this arenaSee my calendar, respond to invites, and create events without leaving the email client | power-user | partialC 6/10 | partialC 3/10 | partialC 2/10 | none 0/10 | fullC 7/10 | n/a |
| Calendar integration — stories about calendar integration in this arenaShare my availability or insert bookable meeting times directly into an email | power-user | fullC 7/10 | none 0/10 | none 0/10 | none 0/10 | none 0/10 | n/a |
Composing sending — stories about composing sending in this arenaComposing sending
Sending
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Composing sending — stories about composing sending in this arenaSee whether and when recipients opened my email | power-user | partialX 6/10 | none 0/10 | none 0/10 | none 0/10 | none 0/10 | none 0/10 |
| Composing sending — stories about composing sending in this arenaSchedule an email to send later and undo a send within a grace window | power-user | none 0/10 | fullC 8/10 | none 0/10 | none 0/10 | fullC 8/10 | none 0/10 |
Templates
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Composing sending — stories about composing sending in this arenaInsert saved snippets or templates — with variables and attachments — instead of retyping the same reply | power-user | partialC 5/10 | partialC 5/10 | fullC 8/10 | none 0/10 | partialC 4/10 | none 0/10 |
Offline reliability — stories about offline reliability in this arenaOffline reliability
Offline
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Offline reliability — stories about offline reliability in this arenaRead, search, and write email offline, with changes syncing when I reconnect | power-user | partialC 5/10 | partialX 3/10 | none 0/10 | none 0/10 | partialC 6/10 | n/a |
Openness — open source, data portability, and self-hosting storiesOpenness
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Openness — open source, data portability, and self-hosting storiesDo everything through the API that I can do in the UI | ai-native | partialT 5/10 | none 0/10 | partialT 4/10 | partialT 6/10 | partialC 5/10 | fullT 8/10 |
| Openness — open source, data portability, and self-hosting storiesExport all of my data in open formats and leave | ai-native | none 0/10 | none 0/10 | none 0/10 | none 0/10 | partialC 4/10 | partialT 5/10 |
| Openness — open source, data portability, and self-hosting storiesRead the product's source under an open license | ai-native | none 0/10 | none 0/10 | none 0/10 | fullT 8/10 | none 0/10 | none 0/10 |
| Openness — open source, data portability, and self-hosting storiesSelf-host the core product | ai-native | none 0/10 | none 0/10 | none 0/10 | fullT 8/10 | none 0/10 | none 0/10 |
Privacy posture — data-handling and privacy storiesPrivacy posture
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Privacy posture — data-handling and privacy storiesChoose where my data is stored (region/residency) | ai-native | none 0/10 | none 0/10 | none 0/10 | partialC 5/10 | none 0/10 | none 0/10 |
| Privacy posture — data-handling and privacy storiesPrevent my data from being used to train AI models | ai-native | none 0/10 | none 0/10 | none 0/10 | partialC 5/10 | none 0/10 | none 0/10 |
| Privacy posture — data-handling and privacy storiesControl data retention and deletion | ai-native | none 0/10 | partialX 3/10 | none 0/10 | partialC 5/10 | none 0/10 | none 0/10 |
| Privacy posture — data-handling and privacy storiesOpt out of telemetry and usage tracking | ai-native | none 0/10 | none 0/10 | none 0/10 | partialT 5/10 | none 0/10 | none 0/10 |
Privacy tracking — stories about privacy tracking in this arenaPrivacy tracking
Protection
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Privacy tracking — stories about privacy tracking in this arenaUse aliases or masked addresses so sign-ups and strangers never learn my real address | switcher | none 0/10 | none 0/10 | none 0/10 | none 0/10 | fullX 8/10 | n/a |
| Privacy tracking — stories about privacy tracking in this arenaThe client protects me from senders' tracking — blocking read pixels by default — and is transparent about what it does with my mail data | switcher | none 0/10 | none 0/10 | none 0/10 | partialC 3/10 | none 0/10 | n/a |
Search history — stories about search history in this arenaSearch history
Migration
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Search history — stories about search history in this arenaImport my complete mail history and contacts from my old provider or client | switcher | none 0/10 | partialX 4/10 | none 0/10 | none 0/10 | partialX 6/10 | n/a |
Search
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Search history — stories about search history in this arenaSearch is fast and precise — operators, filters, and ranked results across my full mail history | power-user | disputedD 4/10 | disputedD 4/10 | partialC 3/10 | partialX 4/10 | partialC 3/10 | partialC 5/10 |
Speed keyboard — stories about speed keyboard in this arenaSpeed keyboard
Shortcuts
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Speed keyboard — stories about speed keyboard in this arenaDo everything from the keyboard — comprehensive shortcuts and a command palette — in an interface fast enough to never make me wait | power-user | disputedD 6/10 | none 0/10 | partialX 6/10 | disputedD 2/10 | partialX 5/10 | none 0/10 |
Team collaboration — stories about team collaboration in this arenaTeam collaboration
Channels
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Team collaboration — stories about team collaboration in this arenaThe same inbox also handles adjacent customer channels — SMS, WhatsApp, social, or live chat — beside email | team-lead | none 0/10 | none 0/10 | partialC 6/10 | none 0/10 | none 0/10 | n/a |
Routing
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Team collaboration — stories about team collaboration in this arenaAssign conversations to teammates and route incoming mail with rules so ownership is explicit | team-lead | partialC 4/10 | partialX 3/10 | fullC 8/10 | none 0/10 | partialC 3/10 | n/a |
Shared inbox
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Team collaboration — stories about team collaboration in this arenaWe can discuss an email in an internal side-thread — comments and @mentions beside the message — instead of forwarding copies around | team-lead | fullC 8/10 | fullC 8/10 | partialC 5/10 | none 0/10 | none 0/10 | n/a |
| Team collaboration — stories about team collaboration in this arenaMy team works shared inboxes together — shared accounts or team channels where everyone sees the same conversation state | team-lead | partialC 6/10 | partialX 5/10 | fullX 9/10 | none 0/10 | none 0/10 | none 0/10 |
Triage inbox — stories about triage inbox in this arenaTriage inbox
Followups
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Triage inbox — stories about triage inbox in this arenaSnooze conversations and set follow-up reminders that resurface a thread if nobody replies | power-user | partialC 6/10 | partialX 4/10 | partialC 6/10 | none 0/10 | partialC 5/10 | n/a |
Inbox structure
| Story | Persona | Superhuman Mail | Shortwave | Missive | Zero | Fastmail | AgentMail |
|---|---|---|---|---|---|---|---|
| Triage inbox — stories about triage inbox in this arenaSelect many conversations at once and archive, label, or mark them done in one stroke | power-user | partialC 3/10 | partialC 4/10 | none 0/10 | partialX 4/10 | partialC 3/10 | none 0/10 |
| Triage inbox — stories about triage inbox in this arenaSplit my inbox into focused streams — important, team, newsletters, calendar invites — so triage happens in priority order, not arrival order | power-user | fullC 8/10 | fullX 8/10 | partialC 4/10 | none 0/10 | partialC 5/10 | n/a |
Verdict✓ fullclear evidence~ partialwith caveats! disputedevidence conflicts— noneno evidence foundn/aquestion doesn't apply to this kind of product
ProofT probedtested by usX communityusers back itC claimedvendor claim onlyD contradictedevidence disagrees⚿ auth-gatedprobe hit a live sign-in wall — verified reachable, untestable keylessly
quality 0–10 · PA Score /100 · A–D = evidence confidence · full guideAdjacent arenas — categories often shopped togetherAdjacent arenas
Shopping this category often means shopping these too.