Arize Phoenix vs Langfuse Comparison
Detailed comparison of features, pricing, and capabilities
Last updated May 15, 2026
Overview
Compare key metrics and features at a glance
Arize Phoenix
https://phoenix.arize.com
Arize Phoenix is an open-source AI observability and evaluation platform developed by Arize AI, designed to help teams monitor, debug, and evaluate large language model (LLM) applications and machine learning models. It provides tools for tracing LLM calls, evaluating model outputs, visualizing embeddings, and identifying issues such as hallucinations, retrieval failures, and prompt problems. Phoenix supports integration with popular frameworks like LangChain, LlamaIndex, and OpenAI, enabling developers to gain deep insights into their AI pipelines throughout the development and production lifecycle.
Langfuse
https://langfuse.com
Langfuse is an open-source LLM engineering platform that provides observability, analytics, and monitoring tools for AI applications built on large language models. It enables developers to trace LLM calls, evaluate model outputs, manage prompts, and debug production issues through a comprehensive dashboard and SDK integrations. The platform supports popular frameworks like LangChain, LlamaIndex, and OpenAI, and can be used as a cloud-hosted service or self-hosted deployment.
Quick Comparison
| Detail | Arize Phoenix | Langfuse |
|---|---|---|
| Category | LLM observability | LLM observability |
| Starting Price | Free | Free |
| Plans Available | 4 | 4 |
| Features Tracked | 18 | 19 |
| Founded | 2020 | 2023 |
| Headquarters | San Francisco, USA | Berlin, Germany |
Features
Detailed feature-by-feature comparison
Feature Comparison
| Feature | | |
|---|---|---|
| api | ||
| LLM Evals SDKs | ||
| compliance | ||
| Compliance Certifications | ||
| core | ||
| Analytics Dashboard | ||
| Cloud Access | ||
| Cloud-Hosted SaaS | ||
| Evaluation Framework | ||
| Experiments | ||
| Experiments and A/B Testing | ||
| Failure and Regression Detection | ||
| LLM Tracing | ||
| Open Source Core | ||
| Performance Monitoring | ||
| Prompt Evaluation | ||
| Prompt Management | ||
| Self‑Hosted Deployment | ||
| Session and User Tracking | ||
| User Feedback Tracking | ||
| Vendor‑Agnostic Observability | ||
| custom | ||
| Extensible Plugin System | ||
| Self-Hosted Deployment | ||
| integration | ||
| Framework Auto‑Instrumentation | ||
| Framework Integrations | ||
| Integration with Arize Production Platform | ||
| LLM Gateway Compatibility | ||
| LLM Provider Support | ||
| Multi‑Language Support | ||
| Notebook Integration | ||
| OpenInference Instrumentation | ||
| OpenTelemetry Integration | ||
| OpenTelemetry Support | ||
| Python SDK | ||
| TypeScript SDK | ||
| security | ||
| Authentication and SSO | ||
| Automated Provisioning / SCIM | ||
| Data Masking | ||
| Project-level RBAC | ||
Pricing
Compare pricing plans and value for money
Arize Phoenix
From $0/mo
Price Components
- Open Source: $0/month
- Trace spans: $0/span (25000 included)
- Ingestion volume: $0/GB (1 included)
- Included GB: $0/GB (100 included)
- Base Fee: $50/month
Best For
Teams building LLM or RAG apps that want open-source observability, deep trace-level debugging, and a path from local development to enterprise deployment.
Langfuse
From $0/mo
Price Components
- base_fee: $0/month
- units: $0/unit (50000 included)
- users: $0/user (2 included)
- base_fee: $29/month
- units: $0/unit (100000 included)
Best For
Development teams prioritizing cost transparency, prompt iteration, and production debugging without framework lock-in or data residency constraints.
Integrations
See which third-party services are supported
Supported Integrations
Coming Soon
Integration comparison data for Arize Phoenix, Langfuse is being collected and will be available soon.
Strengths & Limitations
Key strengths and limitations of each service
Arize Phoenix
Teams building LLM or RAG apps that want open-source observability, deep trace-level debugging, and a path from local development to enterprise deployment.
- Open-source and self-hostable, with OpenTelemetry-based tracing that keeps telemetry in your own stack.
- Strong debugging for RAG and agent workflows, with traces, embedding analysis, and LLM-as-judge evals.
- Broad framework support for LangChain, LlamaIndex, OpenAI, and custom Python apps with minimal code changes.
- Low-friction entry points: free AX for individuals, AX Pro at $50/month, and enterprise SaaS or self-hosted options.
- Managed collaboration and long-term production features live in AX, so pure Phoenix can feel lighter than full SaaS suites.
- Best-in-class observability depth still depends on instrumentation quality and tracing coverage in your app.
- The open-source core is strong for evaluation and debugging, but enterprise governance needs paid AX plans.
Langfuse
Development teams prioritizing cost transparency, prompt iteration, and production debugging without framework lock-in or data residency constraints.
- Open-source with MIT license and self-hosting option via Postgres + ClickHouse, eliminating vendor lock-in and data residency concerns
- ClickHouse acquisition (Jan 2026) dramatically improves trace query performance at scale with 10B+ observations/month capacity
- Most generous free tier in industry (50K units/month, 30-day retention, 2 users) with framework-agnostic OpenTelemetry support across 50+ integrations
- Self-hosting requires infrastructure expertise and maintenance overhead; enterprise-grade on-premise deployments differ significantly from OSS deployments
- Pricing jumps substantially from $29/month (Core) to $199/month (Pro) with limited mid-market tier options for growing teams
Company Info
Company details and background
Arize Phoenix
Langfuse
Comparison FAQ
Common questions about comparing Arize Phoenix and Langfuse
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