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📖 The AI Tool Bible

Arize AI vs Phoenix

A side-by-side look at pricing, capabilities, pros, cons, and our editorial scores.

Arize AI logo
Arize AI
Evaluation
Phoenix logo
Phoenix
Evaluation
Tagline
Arize AI
Enterprise observability and evaluation platform for LLM agents and generative AI applications.
Phoenix
Open-source LLM and agent observability platform with tracing, evals, and experimentation built on OpenTelemetry.
Pricing
Arize AI
Freemium· AX Free: Free · AX Pro: $50 · AX Enterprise: Custom
Phoenix
Freemium· AX Free: Free · AX Pro: $50 · AX Enterprise: Custom
Lowest paid tier
Arize AI
$50 · AX Pro
captured 2026-08-08
Phoenix
$50 · AX Pro
captured 2026-08-08
Free trial
Arize AI
Yes
Phoenix
Yes
API
Arize AI
Yes
Phoenix
Yes
Platforms
Arize AI
api
Phoenix
api
Open source
Arize AI
Yes
Phoenix
Yes
Model used
Arize AI
Multi-model
Phoenix
Multi-model
Best for
Arize AI
Pick Arize if you're running LLM agents or RAG in production and need real tracing, evals, and regression testing rather than ad-hoc logging.
Phoenix
Pick Phoenix if you're building LLM agents and want OpenTelemetry-native tracing and evals you can self-host without losing core features.
Not for
Arize AI
Skip it if you're a solo builder shipping a side project; the OSS Phoenix tool alone will likely cover your needs.
Phoenix
Skip it if you want a fully managed, zero-ops observability SaaS with white-glove enterprise support out of the box.
Editorial score
Arize AI
8.2 / 10
Phoenix
7.0 / 10
Use cases
Arize AI
llm-observabilityagent-evaluationrag-tracingprompt-testingproduction-monitoring
Phoenix
llm-tracingagent-debuggingllm-evaluationprompt-experimentsrag-observability
Pros
Arize AI
  • Strong open-source story via Phoenix and OpenInference
  • Span/trace/session-level evals tuned for agentic workflows
  • Scales to trillions of spans with enterprise compliance (SOC 2, HIPAA, GDPR)
  • Broad framework coverage: LangGraph, LangChain, CrewAI, OpenAI, Anthropic
  • Self-hosted option for regulated deployments
Phoenix
  • Genuinely open source (ELv2) with self-host parity, not a crippled OSS shell
  • Native OpenTelemetry means no vendor lock-in for instrumentation
  • Covers tracing, evals, annotation, and experiments in one tool
  • Framework-agnostic: LangChain, LlamaIndex, DSPy, CrewAI, raw SDK calls all work
Cons
Arize AI
  • Public pricing is opaque; serious usage means a sales call
  • Feature surface is heavy for solo developers or hobby projects
  • Best value assumes you've standardized on OpenInference tracing
Phoenix
  • Self-hosting still requires you to manage storage, retention, and upgrades
  • Eval UX is less polished than some managed competitors like LangSmith
  • Free cloud tier is capped at two instances
Website
Arize AI
arize.com
Phoenix
phoenix.arize.com

Editorial score: rule-based, 0–10, from AI-assisted profile inputs (see /methodology) — not a user rating; “—” means unscored. “Not listed” means we have no record of it, not that it is absent. GitHub figures and prices carry the date they were checked or captured; prices are shown as published, unconverted.

Pick Arize AI if
  • ✅ Strong open-source story via Phoenix and OpenInference
  • ✅ Span/trace/session-level evals tuned for agentic workflows
  • ✅ Scales to trillions of spans with enterprise compliance (SOC 2, HIPAA, GDPR)
  • ✅ Broad framework coverage: LangGraph, LangChain, CrewAI, OpenAI, Anthropic
Pick Phoenix if
  • ✅ Genuinely open source (ELv2) with self-host parity, not a crippled OSS shell
  • ✅ Native OpenTelemetry means no vendor lock-in for instrumentation
  • ✅ Covers tracing, evals, annotation, and experiments in one tool
  • ✅ Framework-agnostic: LangChain, LlamaIndex, DSPy, CrewAI, raw SDK calls all work
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