What is Langfuse?
Langfuse is an open source platform for observability and evaluation of AI agents and LLM applications. It records hierarchical traces of every LLM call, tool invocation and retrieval step, and lets you filter them by user, session, cost, latency or custom metadata. The same data feeds evaluations, where you can use LLM-as-a-judge, heuristic functions or human review on production traces or during experiments.
Teams use it to manage prompts separately from code with one-click deployments and rollbacks, test prompts on real inputs in a playground, define datasets and run experiments that compare results side by side, and monitor cost, latency and quality through dashboards and alerts. The product is available as a hosted cloud service or self-hosted via Docker Compose, Kubernetes or Terraform, and it works with any language supporting OpenTelemetry plus over 100 framework and model provider integrations.
Key features
- Hierarchical tracing of LLM calls, tool invocations and retrieval steps
- Evaluation with LLM-as-a-judge, heuristic functions or human annotation
- Prompt management with versioning, deployments and rollbacks
- Playground and experiments comparing models and prompts side by side
- Dashboards and alerts for cost, latency and quality
- Self-hosting under MIT license with REST APIs and exports
Who is it for
- AI engineers and developers
- ML and LLM engineering teams
- Product teams running AI agents in production
- Enterprises needing self-hosted observability
How to get started with Langfuse
- Create a free Hobby account on the Langfuse website, no credit card required.
- Install the Langfuse SDK or set up an integration with your framework.
- Connect your app so it sends traces of LLM, tool and retrieval calls.
- You build AI agents and want to see exactly what each step does.
- You need to evaluate production data using LLM-as-a-judge, heuristics or manual annotation.
- You want to version prompts outside code and compare models in one place.
- You need a Polish-language interface, which is not available.
- Your small team needs many units or longer data retention on a tight budget, since paid plans are expensive.
Pros and cons
- Open source under MIT license with self-hosting options
- Works with any stack via OpenTelemetry and 100+ integrations
- Data portability with REST APIs and S3 blob export
- Free plan limited to 50k units per month and 30 days data access
- Per-user and per-volume pricing grows quickly at higher tiers
Langfuse pricing
| Plan | Price | Includes |
|---|---|---|
| Hobby | 0 USD / month | 50k units/month, 30 days data access, 2 users, community support |
| Core | 29 USD / month | 100k units/month included, additional 8 USD per 100k units, 90 days data access, unlimited users, in-app support |
| Pro | 199 USD / month | 100k units/month included, additional 8 USD per 100k units, 3 years data access, data retention management, unlimited annotation queues, high rate limits, SOC2 and ISO27001 reports, HIPAA-ready region, prioritized support; optional Teams add-on 300 USD/mo |
| Enterprise | 2499 USD / month | 100k units/month included, additional 8 USD per 100k units, SSO, SCIM API, audit logs, custom rate limits, uptime and support SLA, named lead support engineer; talk to sales |
Prices copied from Langfuse pricing, checked October 12, 2026. Currency as shown by the vendor; taxes may apply.
Is Langfuse free?
Yes, there is a free plan. Hobby plan: all platform features with limits, 50k units per month, 30 days data access, 2 users, community support via GitHub. No credit card required.
Langfuse alternatives
| Tool | Price from | Free plan | Category |
|---|---|---|---|
 Google AI Studio | 0,75 USD | ? | APIs & models |
 Runpod | 0.74 USD/mo | trial | APIs & models |
 Cline | not listed | yes | APIs & models |
 Ollama | 20 USD/mo | yes | APIs & models |
 Amazon Bedrock | od 0,20 USD | ? | APIs & models |
 Claude Platform (Anthropic API) | 2 USD input / 10 USD output | no | APIs & models |
All alternatives to Langfuse →
FAQ
What is Langfuse used for?
Open source platform to trace, evaluate and improve AI agents and LLM apps using production data, for engineering teams.
Is Langfuse free?
Yes, there is a free plan. Hobby plan: all platform features with limits, 50k units per month, 30 days data access, 2 users, community support via GitHub. No credit card required.
How much does Langfuse cost?
The cheapest paid plan is 29 USD/mo (vendor pricing, October 12, 2026).
What are the best Langfuse alternatives?
Closest alternatives: Google AI Studio, Runpod, Cline, Ollama, Amazon Bedrock.
Data checked October 12, 2026 on the vendor website (langfuse.com).