About Langfuse
Overview
Langfuse is an open source LLM observability and evaluation platform that helps engineers trace, evaluate, and improve AI agents. It connects tracing, monitoring, datasets, experiments, and evaluation in one continuous loop.
Built for teams building AI applications with LLMs, Langfuse supports any language and framework via OpenTelemetry instrumentation and offers 100+ integrations. It is used by 19 of the Fortune 50 and over 100,000 engineers processing 10+ billion observations per month.
Key Benefits
- Hierarchical traces capture every LLM call, tool invocation, and retrieval step with filtering by user, session, cost, latency, or custom metadata.
- LLM-as-a-judge, heuristic functions, or human review — run evaluators on production data or during experiments.
- Separate prompts from code with one-click deployments and rollbacks, making prompt improvement a team activity.
- Test prompts on real production inputs and compare models side-by-side in the Playground.
- Define test cases, run experiments, and compare results side by side with the Experiments feature.
- Collaborative human-in-the-loop workflows let teams review traces and create golden datasets together.
How It Works
You instrument your LLM application using Langfuse SDKs (Python, JavaScript, TypeScript), OpenTelemetry, or proxy-based logging via LiteLLM. Traces flow into the platform where you filter by user, session, cost, latency, or custom metadata. You then run LLM-as-a-judge or heuristic evaluators, manage prompt versions with one-click rollbacks, and define experiments on datasets — all from the same interface.
Use Cases
- AI engineering teams at large enterprises — debug and improve production LLM agents by tracing every tool invocation and LLM call.
- Startup founders building AI products — evaluate prompt quality and model cost before shipping to users.
- Machine learning engineers — run offline experiments comparing model outputs side by side to select best-performing prompts and models.
- Platform engineering teams — self-host Langfuse with Docker Compose, Kubernetes, or cloud Terraform to keep data inside their infrastructure.
- Generative design teams like Canva's AI team — trace and debug generative design features running in production.
- Open source contributors and hobbyists — get started free with the Hobby plan to trace personal AI projects without a credit card.
Why Choose This Product
Langfuse is best suited for engineering teams that need one integrated platform for tracing, prompt management, evaluation, and experimentation rather than stitching together multiple tools. It is open source under the MIT license, supports self-hosting at scale, and does not lock in data — all product features are available in the MIT-licensed version.
Langfuse Pros & Cons
- Open source under MIT license with all features available
- Used by 19 of Fortune 50 companies
- 100+ integrations with major frameworks and providers
- Self-hosting options via Docker, Kubernetes, and Terraform
- Free tier with no credit card required
Key Features
Hierarchical Traces
Captures every LLM call, tool invocation, and retrieval step with filtering by user, session, cost, latency, or custom metadata.
LLM-as-Judge Evals
Run LLM-as-a-judge, heuristic functions, or human review evaluators on production data or during experiments.
Prompt Management
Separate prompts from code with one-click deployments and rollbacks, making prompt improvement a team activity.
Playground
Test prompts on real production inputs and compare models side by side.
Experiments
Define test cases and run experiments, then compare results side by side.
Human Annotation
Collaborative human-in-the-loop workflows to review traces and create golden datasets.
Cost and Latency Monitoring
Monitor cost, latency, and quality with dashboards and automated alerts.
Self-Hosting
Deploy via Docker Compose, Kubernetes (Helm), or Terraform on AWS, GCP, and Azure.
Langfuse Pricing
View full pricing →- 50k units/month included
- 30 days data access
- 2 users
- Community support via GitHub
- All platform features with limits
- 100k units/month included
- 90 days data access
- Unlimited users
- In-app support
- Additional usage $8/100k units
- 100k units/month included
- 3 years data access
- Data retention management
- Unlimited annotation queues
- High rate limits
- SOC2 & ISO27001 reports, HIPAA-ready region
- Enterprise SSO (e.g. Okta)
- SSO enforcement
- Fine-grained RBAC
- Support via Dedicated Slack / MS Teams Channel
- 100k units/month included
- Audit Logs
- SCIM API
- Uptime SLA
- Support SLA
- Dedicated support engineer
| Feature | Hobby Free/mo | Core $29/mo | Pro $199/mo | Teams $300/mo | Enterprise $2499/mo |
|---|---|---|---|---|---|
| 50k units/month included | |||||
| 30 days data access | |||||
| 2 users | |||||
| Community support via GitHub | |||||
| All platform features with limits | |||||
| 100k units/month included | |||||
| 90 days data access | |||||
| Unlimited users | |||||
| In-app support | |||||
| Additional usage $8/100k units | |||||
| 3 years data access | |||||
| Data retention management | |||||
| Unlimited annotation queues | |||||
| High rate limits | |||||
| SOC2 & ISO27001 reports, HIPAA-ready region | |||||
| Enterprise SSO (e.g. Okta) | |||||
| SSO enforcement | |||||
| Fine-grained RBAC | |||||
| Support via Dedicated Slack / MS Teams Channel | |||||
| Audit Logs | |||||
| SCIM API | |||||
| Uptime SLA | |||||
| Support SLA | |||||
| Dedicated support engineer |
Pricing extracted from the product website and may change. Check the source for current details.
Frequently asked questions about Langfuse
Is Langfuse free to get started?
Yes, the Hobby plan is free with no credit card required. It includes 50k units per month, 30 days data access, 2 users, and community support via GitHub.
Can I self-host Langfuse?
Yes, Langfuse supports self-hosting at scale via Docker Compose, Kubernetes (Helm), and Terraform for AWS, GCP, and Azure. All product features are MIT licensed.
What integrations does Langfuse support?
Langfuse works with any language via OpenTelemetry and has 100+ integrations including LangChain, Vercel AI SDK, LiteLLM, Pydantic AI, CrewAI, OpenAI, Anthropic, and Amazon Bedrock.
Is Langfuse free?
Langfuse offers a free plan with optional paid upgrades. See the pricing section for what's included in each tier.
How much does Langfuse cost?
Langfuse offers the following plans: Hobby, Core, Pro, Teams, Enterprise. See the pricing section for what's included in each tier and any per-seat or usage-based costs.
What platforms does Langfuse support?
Langfuse is available on: Web.
How Langfuse compares
LangfuseThis | ||
|---|---|---|
| Starting price | Free | Free |
| Pricing model | Freemium | Freemium |
| Platforms | Web | — |
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| Rating | — | — |
