Arize Phoenix vs Langfuse

Detailed side-by-side comparison to help you choose the right tool

Arize Phoenix

🔴Developer

AI Observability

Arize Phoenix is an open-source AI observability and evaluation platform for tracing, testing, and improving LLM applications and agents.

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Starting Price

Free
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Langfuse

🔴Developer

AI observability

An open-source observability and evaluation platform for language-model applications.

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Starting Price

Free
Full ReviewVisit Site

Feature Comparison

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FeatureArize PhoenixLangfuse
CategoryAI ObservabilityAI observability
Pricing Plans4 listed plans5 listed plans
Starting PriceFreeFree
Key Features
  • • LLM Tracing & Observability
  • • Evaluation Framework
  • • Experiment Management
  • • Hierarchical Tracing & Agent Debugging
  • • Production Prompt Management & Versioning
  • • LLM-as-Judge Evaluation Framework

Arize Phoenix - Pros & Cons

Pros

  • ✓Open-source Phoenix can run locally or on controlled infrastructure without a software license fee.
  • ✓OpenTelemetry tracing reduces instrumentation lock-in.
  • ✓Datasets, experiments, evaluations, and Prompt IDE connect evidence to changes.
  • ✓AX Free and Pro include unlimited users and evaluations at published prices.

Cons

  • ✗Self-hosting shifts upgrades, storage, access control, backups, and availability to the user's team.
  • ✗Agent runs can generate many spans, consuming 25,000 or 50,000 allowances quickly.
  • ✗Managed retention of 15 or 30 days may be short for audits or long incident cycles.
  • ✗Fetched pages did not explicitly document native MCP support.

Langfuse - Pros & Cons

Pros

  • ✓Open source with free self-hosting — full feature parity without usage limits
  • ✓Free Hobby tier on cloud with no credit card — lowest barrier to entry in the category
  • ✓Trace graphs for multi-agent systems are genuinely useful for debugging complex failures
  • ✓Prompt management + evals turns prompt engineering into a systematic, measurable process
  • ✓40,000+ builders using it — extensive community resources and integrations
  • ✓Integrates natively with LangChain, LlamaIndex, OpenAI SDK, and Anthropic

Cons

  • ✗Pro plan units pricing ($8/100k) can add up for high-volume production applications
  • ✗Enterprise SSO requires the $300/month Teams add-on on top of Pro — costly for mid-size teams
  • ✗Self-hosting requires Docker/Kubernetes operational knowledge
  • ✗UI can feel overwhelming for teams who just want simple cost/latency dashboards
  • ✗Real-time alerting features are less developed than commercial-first alternatives like Arize
  • ✗Enterprise tier at $2,499/month is priced for large organizations — no mid-market option

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🔒 Security & Compliance Comparison

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Security FeatureArize PhoenixLangfuse
SOC2✅ Yes✅ Yes
GDPR✅ Yes✅ Yes
HIPAA❌ No✅ Yes
SSO❌ No✅ Yes
Self-Hosted✅ Yes—
On-Prem✅ Yes✅ Yes
RBAC❌ No✅ Yes
Audit Log❌ No✅ Yes
Open Source✅ Yes✅ Yes
API Key Auth✅ Yes✅ Yes
Encryption at Rest✅ Yes✅ Yes
Encryption in Transit✅ Yes✅ Yes
Data ResidencyAvailableUS, EU, SELF-HOSTED
Data Retentionconfigurableconfigurable
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Review Arize PhoenixReview Langfuse