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Langfuse (ClickHouse) vs Arize AI. Rows marked Differs have different values.

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Langfuse (ClickHouse)

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Arize AI

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TypeStartupStartup
Categories
In one lineOpen-source LLM engineering platform: tracing, prompts, evals.Observability and evaluation for AI — makers of OSS Phoenix.
Stage & fundingDiffersY Combinator · Acquired by ClickHouse (Jan 2026)—
GitHub stars——
License——
Language——
Last push——
Works with——
Built on——
Built on it——
Similar toDiffers
People linked22
Events00
Pros
  • DocsCore features are MIT-licensed and free to self-host with Docker Compose or Kubernetes, and ClickHouse committed to keeping that license after the acquisition.[1][2]
  • DocsThe free Hobby cloud tier includes 50k units per month, 2 users and 30 days of data access with no credit card.[1]
  • MetadataWidely adopted, with more than 20,000 GitHub stars and over 26 million SDK installs per month at the end of 2025.[1]
  • DocsPro costs $199/month and adds 3 years of data access, data-retention controls, SOC2/ISO27001 reports and an available HIPAA BAA.[1]
  • MetadataPhoenix is free to self-host and very active (about 12k stars, commits on 29 Oct 2026).[1][2]
  • User reportsBuilt on OpenTelemetry and OpenInference, so traces are portable; users praise OpenInference, and a community proxy sends Claude Code spans to Phoenix.[1][2]
  • User reportsPractitioners use Phoenix for LLM-as-judge plus code-based evals and continuous analysis of production traces.[1][2]
  • DocsEvery AX plan, including Free, has unlimited users and evals, and AX Pro costs $50/month.[1]
Cons
  • Independent testSelf-hosting v3 means running ClickHouse, Redis, blob storage, a worker and Postgres instead of v2's single container, and guides cite about 4 cores and 9GB RAM as the minimum.[1][2]
  • User reportsSelf-hosters report that a Redis outage or out-of-memory error stops event processing entirely, along with recurring ClickHouse migration failures and stuck trace deletion.[1]
  • DocsEnterprise SSO and fine-grained RBAC need the $300/month Teams add-on on top of Pro, and audit logs and SCIM need the $2,499/month Enterprise plan.[1]
  • MetadataClickHouse now owns it and plans tighter integration with its database, so a data-platform vendor sets the long-term roadmap.[1]
  • MetadataPhoenix uses the Elastic License 2.0, which is source-available rather than OSI open source and restricts offering it as a managed service.[1]
  • DocsAX Free caps you at 25k spans a month with 15-day retention, and Pro raises that only to 50k spans and 30 days.[1]
  • DocsSelf-hosted AX, SSO and audit logs are Enterprise-only.[1]
  • User reportsOne user found Arize's Claude Code tracing setup heavyweight, and others dropped Phoenix after reviewing its site.[1][2]
  • MetadataPhoenix has about 1,000 open GitHub issues.[1]
Best forTeams that want open-source LLM tracing, prompt management and evals with a real option to self-host.Teams that want OpenTelemetry-native LLM tracing and evals they can run themselves with Phoenix, with a hosted option later.
Watch out forSelf-hosted v3 is a multi-service deployment, so budget ops time or use the cloud tiers.AX Free and Pro have low span and retention caps, and ELv2 limits offering Phoenix as a service.
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