Langfuse vs Ragas (2026)
Overview
Langfuse is an open-source LLM engineering platform for tracing, evals, and prompt management, self-hosted or on Langfuse Cloud with a free plan.
Ragas is an open-source evaluation framework specifically designed for RAG (Retrieval-Augmented Generation) pipelines. It provides metrics for context precision, context recall, faithfulness, and answer relevancy, helping teams measure and improve the quality of their RAG systems. Ragas has become the standard evaluation toolkit for teams building production RAG applications.
Key features
Core capabilities each platform advertises.
- Tracing for LLM calls, tool runs, and agent steps
- Python and TypeScript SDKs plus OpenTelemetry
- LLM-as-a-judge and custom evaluations
- Datasets and experiments
- Prompt management and playground
- RAG-specific evaluation framework
- Component-wise metrics for RAG
- Synthetic test data generation
- LLM-as-judge evaluators
- Open-source Python library
Strengths and tradeoffs
What each tool does well, and the limitations to keep in mind.
Pros
- MIT-licensed core, self-hostable with Docker Compose or Kubernetes
- Tracing, evals, and prompt management in one tool
- Unlimited users on paid cloud plans
- Free Hobby plan with 50k units a month
- Native SDKs plus OpenTelemetry for other languages
Cons
- No LLM gateway, so routing, failover, and spend limits need a separate tool
- Hobby plan keeps 30 days of data and caps at 2 users
- Enterprise SSO and RBAC need the $300/month Teams add-on on Pro
- Self-hosting means running and scaling Langfuse's services yourself
Pros
- Specialized focus on RAG evaluation with metrics specifically designed for retrieval systems
- Open-source framework providing transparency and community-driven development
- Strong industry endorsement from OpenAI, LangChain, and LlamaIndex
- Y Combinator backing providing credibility and potential for growth
- Easy integration with popular frameworks like LangChain and LlamaIndex
Cons
- Very small team of 3 employees may limit support and feature development
- Limited to RAG evaluation, not a comprehensive observability solution
- Minimal funding ($500K) compared to competitors may impact long-term sustainability
- Lack of clear commercial pricing model for enterprise features
Langfuse or Ragas — which should you choose?
Choose Langfuse if you wantChoose if you want
- Tracing and debugging LLM apps and agents
- Self-hosting LLM observability
- Versioning prompts across environments
- Scoring outputs with LLM judges and human review
Choose Ragas if you wantChoose if you want
- Evaluating RAG pipeline quality end-to-end
- Measuring retrieval precision and recall
- Testing faithfulness and answer relevance
- Generating synthetic evaluation datasets
- Benchmarking RAG across configurations
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