Langfuse: Open Source Alternative to LangSmith

Langfuse is an open-source LLM engineering platform with 28k+ GitHub stars — a LangSmith alternative for tracing, debugging, and monitoring AI applications.

Compare Langfuse with Braintrust and Arize Phoenix before you choose your stack.

Key features

Tracing

• Full observability for LLM chains and agents
• Automatic instrumentation for LangChain, LlamaIndex
• Custom trace spans and events
• Session and user tracking

Prompt management

• Version-controlled prompts
• A/B testing and experiments
• Playground for prompt iteration
• Git-like prompt versioning

Analytics

• Cost tracking per model and prompt
• Latency and quality metrics
• Dataset evaluation and scoring
• Custom dashboards

Langfuse vs LangSmith

	Langfuse	LangSmith
License	MIT (open source)	Proprietary
Data residency	Self-hosted option	Vendor cloud
Privacy	No third-party tracking by default	Vendor analytics pipeline
Customization	SQL and plugin extensibility	Limited to product UI
Cost	Free tier + self-hosting	Usage-based SaaS

Choose Langfuse if you want open-source code, self-hosting options, and full control over your data and deployment.

Choose LangSmith if you prefer a managed proprietary product with vendor support and minimal setup.

Browse more open-source alternatives to LangSmith, or explore other tools in Analytics.

At a glance

License	MIT
Stack	TypeScript, Python
Self-hosted	Yes
Cloud	cloud.langfuse.com
SDKs	Python, TypeScript, Go

Self-hosting

docker compose up -d

Requires PostgreSQL and ClickHouse (or Postgres for small deployments).

FAQ

Is Langfuse a free alternative to LangSmith?

Yes. Langfuse is open source under MIT. You can self-host it at no software cost — you only pay for infrastructure or optional managed services.

How does Langfuse compare to LangSmith?

Langfuse gives you source code access, self-hosting, and data ownership. LangSmith is a proprietary product focused on managed convenience. See the comparison table above for a side-by-side breakdown.

Can I self-host Langfuse?

Yes. Langfuse supports self-hosted deployment, which is a core reason teams choose it over LangSmith. Check the Getting started or Self-hosting section for install commands.

Is Langfuse suitable for production?

Langfuse is actively maintained with a strong open-source community. Many teams run it in production as a Analytics alternative to LangSmith. Review the At a glance table for license and stack details.

What are alternatives to Langfuse and LangSmith?

Browse alternatives to LangSmith for more open-source options, including tools compared to Braintrust. Explore the full Analytics category for related projects.