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Rank #6 of 8 in LLM Evals & Observability

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Arize Phoenix

Open Source

Arize AI, Inc.

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Install

pippip install arize-phoenix
dockerdocker run -p 6006:6006 -p 4317:4317 arizephoenix/phoenix:latest

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Alternatives to Arize Phoenix

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Arize Phoenix homepage screenshot
homepage · captured Sep 2026 · view live ↗
Arize Phoenix docs screenshot
docs · captured Sep 2026 · view live ↗

Verified integrations

Connections to other tracked products — hover a chip for the verbatim evidence quote behind it.

By theme — the product's score on each story themeBy theme

Agenticness — how well agents can access and operate the productAgenticnessevidence →

How well agents can access and operate the product

34.6/100

Alerting dashboards — stories about alerting dashboards in this arenaAlerting dashboardsevidence →

Stories about alerting dashboards in this arena

0.0/100

Automation depth — how much of the product can run unattendedAutomation depthevidence →

How much of the product can run unattended

11.3/100

Cost monitoring — stories about cost monitoring in this arenaCost monitoringevidence →

Stories about cost monitoring in this arena

27.6/100

Data access export — stories about data access export in this arenaData access exportevidence →

Stories about data access export in this arena

0.0/100

Evals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasetsevidence →

Measuring quality — datasets, eval runs, regression tracking

61.8/100

Openness — open source, data portability, and self-hosting storiesOpennessevidence →

Open source, data portability, and self-hosting stories

49.8/100

Privacy posture — data-handling and privacy storiesPrivacy postureevidence →

Data-handling and privacy stories

34.7/100

Prompt management — stories about prompt management in this arenaPrompt managementevidence →

Stories about prompt management in this arena

80.0/100

Tracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentationevidence →

Instrumenting code and tracing requests end to end

65.1/100

Story verdicts — every judged story with its evidenceStory verdicts

What’s free: 8 free · 0 paid · 0 enterprise · 29 not stated in evidence

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Sorted by importance (agentic first) (high → low) · 52/52 stories · click a row’s chevron for the rationale and evidence

Connect an agent via an official MCP server G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness3full8/10T

Drive the product through a documented public API G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness3full7/10T

Delegate tasks to a built-in AI assistant inside the product G

Agentic features

ai-native userAgenticness — how well agents can access and operate the productAgenticness3none0/10

Plug MCP servers into this product so it can use their tools G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness3n/a0/10

Point an agent at llms.txt or agent-oriented docs G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness2full9/10T

Build against official SDKs G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness2full8/10C

Operate the product with natural-language commands G

Agentic features

ai-native userAgenticness — how well agents can access and operate the productAgenticness2full7/10T

Run the product headlessly / in CI for automation G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness2partialfree7/10C

Use an official CLI G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness2partial6/10C

Get AI-generated insights and suggestions from my data inside the product G

Agentic features

ai-native userAgenticness — how well agents can access and operate the productAgenticness2partial5/10C

Download a machine-readable API spec (OpenAPI or equivalent) G

Api quality

ai-native userAgenticness — how well agents can access and operate the productAgenticness2none0/10

Explore an interactive API reference with runnable examples G

Api quality

ai-native userAgenticness — how well agents can access and operate the productAgenticness2none0/10

Rely on versioned APIs with a documented deprecation policy G

Api quality

ai-native userAgenticness — how well agents can access and operate the productAgenticness2none0/10

Issue scoped/least-privilege API credentials for an agent G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness2noneuntestednone yet

Set up automations that run autonomously in the background G

Agentic features

ai-native userAgenticness — how well agents can access and operate the productAgenticness2noneuntestednone yet

Subscribe to events via webhooks G

Agent access

ai-native userAgenticness — how well agents can access and operate the productAgenticness2noneuntestednone yet

Test against a sandbox environment without touching production data G

Api quality

ai-native userAgenticness — how well agents can access and operate the productAgenticness1partialfree5/10C

Capture traces of my LLM calls with inputs, outputs, latency, and token usage C

Trace capture

developerTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation3full9/10C

Score outputs with configurable LLM-as-a-judge evaluators C

Offline evals

ml engineerEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets3full9/10C

Self-host the core product G

ai-native userOpenness — open source, data portability, and self-hosting storiesOpenness3fullfree9/10C

Send and receive traces over OpenTelemetry (OTLP) instead of a proprietary format C

Trace capture

developerTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation3full9/10C

Compare eval runs side by side to catch regressions between prompt or model versions C

Offline evals

ml engineerEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets3full8/10C

Curate datasets from production traces and run offline evaluations against them C

Offline evals

ml engineerEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets3full8/10C

Have an agent query my traces, metrics, and eval results through an API or MCP server to debug my app C

Ai observability

ai-native userTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation3full8/10T

Version prompts and deploy changes to production without shipping code C

Prompt workflow

developerPrompt management — stories about prompt management in this arenaPrompt management3full8/10C

Export all of my data in open formats and leave G

ai-native userOpenness — open source, data portability, and self-hosting storiesOpenness3partialfree6/10C

Prevent my data from being used to train AI models G

ai-native userPrivacy posture — data-handling and privacy storiesPrivacy posture3partialfree6/10C

See cost and token usage per request, model, and time period in dashboards C

Cost tracking

developerCost monitoring — stories about cost monitoring in this arenaCost monitoring3partial5/10C

Define rules that trigger actions automatically on events G

ai-native userAutomation depth — how much of the product can run unattendedAutomation depth3noneuntestednone yet

Instrument my app through existing integrations for frameworks like LangChain, the OpenAI SDK, or the Vercel AI SDK C

Trace capture

developerTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation2full8/10C

Iterate on prompts in a playground against real models and variables C

Prompt workflow

developerPrompt management — stories about prompt management in this arenaPrompt management2full8/10C

Trace multi-step agent runs as nested spans grouped into sessions or threads C

Trace capture

developerTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation2full8/10C

Write custom code-based scorers and metrics for my evaluations C

Offline evals

ml engineerEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets2full8/10C

Choose where my data is stored (region/residency) G

ai-native userPrivacy posture — data-handling and privacy storiesPrivacy posture2partialfree6/10C

Have an agent create a dataset, trigger an eval run programmatically, and read back the results C

Ai eval ops

ai-native userEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets2partial6/10C

Instrument apps in both Python and JS/TS with officially supported SDKs G

Sdk coverage

developerTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation2partial6/10C

Opt out of telemetry and usage tracking G

ai-native userPrivacy posture — data-handling and privacy storiesPrivacy posture2partialfree6/10C

Route outputs to human annotation queues for review and labeling C

Human review

ml engineerEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets2partial6/10C

Control data retention and deletion G

ai-native userPrivacy posture — data-handling and privacy storiesPrivacy posture2partialfree5/10C

Do everything through the API that I can do in the UI G

ai-native userOpenness — open source, data portability, and self-hosting storiesOpenness2partial5/10T

Perform bulk operations across many items at once G

ai-native userAutomation depth — how much of the product can run unattendedAutomation depth2partial5/10C

Read the product's source under an open license G

ai-native userOpenness — open source, data portability, and self-hosting storiesOpenness2partial5/10C

Run evals in CI and gate deployments on their results C

Offline evals

developerEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets2partial5/10C

Run evaluators continuously on live production traffic, not just offline datasets C

Online evals

ml engineerEvals datasets — measuring quality — datasets, eval runs, regression trackingEvals datasets2partial5/10C

Attribute cost and usage to users, sessions, and features via custom metadata C

Cost tracking

developerCost monitoring — stories about cost monitoring in this arenaCost monitoring2partial4/10C

Bulk-export traces and datasets to blob storage or my data warehouse C

Data export

developerData access export — stories about data access export in this arenaData access export2none0/10

Build custom dashboards over latency, error, cost, and eval-score metrics C

Monitoring

ml engineerAlerting dashboards — stories about alerting dashboards in this arenaAlerting dashboards2noneuntestednone yet

Mask or redact sensitive data before it is stored in traces C

Data controls

developerTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation2noneuntestednone yet

Schedule recurring jobs or workflows G

ai-native userAutomation depth — how much of the product can run unattendedAutomation depth2noneuntestednone yet

Set alerts on error rates, cost spikes, or eval-score drops and get notified in Slack, PagerDuty, or email C

Monitoring

developerAlerting dashboards — stories about alerting dashboards in this arenaAlerting dashboards2noneuntestednone yet

Version, review, and roll back my automations G

ai-native userAutomation depth — how much of the product can run unattendedAutomation depth1partial5/10C

Capture multimodal payloads (images, audio, files) inside my traces C

Trace capture

developerTracing instrumentation — instrumenting code and tracing requests end to endTracing instrumentation1none0/10

Opportunities — the stories that would move this product's scores, from its own judged verdictsOpportunitiestop 8 of 34 stories with headroom

What would move Arize Phoenix’s scores — derived from its own judged verdicts, biggest headroom first. Each line quotes what the judge found missing; shipping it (or evidencing it publicly) is the fix.

  1. Agenticness — how well agents can access and operate the productDelegate tasks to a built-in AI assistant inside the product

    nonemoves Built-in AIimpact 45

    Phoenix is an observability/evaluation platform; the evidence describes tracing, evals, prompt management, datasets, and an MCP server that lets *external* agents (Claude Code, Cursor, etc.) operate on Phoenix data — not a built-in AI assistant living inside Phoenix that users delegate tasks to.

  2. Automation depth — how much of the product can run unattendedDefine rules that trigger actions automatically on events

    nonemoves PA Scoreimpact 30

    Phoenix's evidence covers tracing, evaluation, datasets, prompt management, and MCP integration, but nothing describes a rules/triggers engine that automatically fires actions on events (e.g., alerting, auto-remediation, webhooks on thresholds).

  3. Agenticness — how well agents can access and operate the productSet up automations that run autonomously in the background

    nonemoves Built-in AIimpact 30

    Phoenix's evidence covers tracing, evaluation, prompt management, and datasets, but nothing describes scheduled or autonomous background automations (e.g., recurring eval jobs, alerting rules, or triggers) that run without user initiation.

  4. Agenticness — how well agents can access and operate the productIssue scoped/least-privilege API credentials for an agent

    nonemoves agent-readyimpact 30

    No evidence in the pack describes scoped or least-privilege API key/credential issuance for agents; Phoenix's docs cover tracing, evaluation, prompt management, and an MCP endpoint, but nothing about credential scoping or access control granularity.

  5. Agenticness — how well agents can access and operate the productSubscribe to events via webhooks

    nonemoves agent-readyimpact 30

    No evidence anywhere in the pack of a webhook subscription mechanism; Phoenix's integration surface is OTLP tracing ingestion, an MCP server, and SDKs, but nothing about outbound event webhooks for subscribing to Phoenix events.

  6. Agenticness — how well agents can access and operate the productExplore an interactive API reference with runnable examples

    nonemoves API qualityimpact 30

    Docs mention an 'sdk-api-reference' page listing decorators and SDK features, but there is no evidence of an interactive, runnable API reference (e.g., a Swagger/OpenAPI explorer or live code sandbox); a direct probe for OpenAPI/swagger specs returned 404 on all candidate paths, indicating no such interactive reference is discoverable.

  7. Agenticness — how well agents can access and operate the productDownload a machine-readable API spec (OpenAPI or equivalent)

    nonemoves API qualityimpact 30

    Missing: any OpenAPI/Swagger spec, documented REST API reference, or SDK-generated schema.

  8. Agenticness — how well agents can access and operate the productRely on versioned APIs with a documented deprecation policy

    nonemoves API qualityimpact 30

    Evidence shows only generic container/image version pinning (e.g., 'version-8.0.0' Docker tags) but no documented API versioning scheme or deprecation policy for Phoenix's SDK/API; an OpenAPI probe also returned 404s, finding no formal API spec to review versioning against.

Showing the top 8 of 34 — every none/partial verdict in the story verdicts table is headroom.

Think a verdict is wrong? Every verdicts-table row has a Flag link — see the methodology.

Coverage map — which docs area, API section, or community source covers which judged storiesCoverage map5 surfaces · 37 covered stories

Where the cited evidence behind each covered verdict came from — the same citations the verdicts table shows, no extra judging.

docs37 stories

Claims vs evidence — vendor claims reconciled against independent verdictsClaims vs evidence

2 of 20 testable claims verified · 1 contradictedintegrity 0/100

39 distinct capability claims found in Arize Phoenix’s own claimed-docs/GitHub materials, reconciled against our judge’s independent verdicts.

2

Verified

17

Unverified

1

Contradicted

18

Undersold

Verified (3)
Unverified (37)
Contradicted (1)
Undersold (18)
Claims outside our story set (8)

Real capability claims found in Arize Phoenix’s own materials, but no story in this arena’s taxonomy covers them yet — that’s feedback on the taxonomy, not a mark against the product.

  • Debug by replaying LLM calls with different inputs (span replay)

    source ↗
  • Identify and address slow invocations of LLMs, retrievers, and other components

    source ↗
  • Inspect retrieved documents from a Retriever call including score and order

    source ↗
  • View tool descriptions and function signatures available to the LLM

    source ↗
  • Organize traces into separate projects per application

    source ↗
  • Run thousands of evaluations without writing retry or concurrency logic

    source ↗
  • Use trace viewer to explore eval traces and identify systematic evaluator bias

    source ↗
  • Every evaluation run captures inputs, exact judge prompts, model reasoning, scores, and timing

    source ↗
Suggest a story for these →

Business model

open-sourcefree-tierusage-basedenterprise-custom

Phoenix is fully open source (ELv2) and free to self-host with no feature gates; Phoenix Cloud has a free tier, and Arize's paid AX platform (usage/custom pricing) sits above it.

pricing ↗

Score trend

How this product’s scores have moved as evidence and verdicts are re-derived — a point per change, not per day.

PA Score32 (Sep 4 '26)32 (Sep 4 '26)
Agent-ready40 (Sep 4 '26)53 (Sep 4 '26)

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Think a verdict is wrong? Opens a prefilled GitHub issue — or use the ⚑ next to any verdict above.

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For agents

Data

Agent surface uptime llms.txt 100% (30d, checked every 6h since Sep 8 '26)