LangChain

LangChainSince 2022-10

The most popular framework for developing applications powered by large language models, including agents and RAG.

Provides components for memory, data retrieval, and tool usage.

LangfuseSince 2025-06

Langfuse is an open-source LLM engineering and observability platform built for teams developing production-grade generative AI applications and autonomous multi-agent pipelines. It captures granular traces across token usage, prompt versions, latency bottlenecks, and retrieval accuracy, giving developers complete visibility into model behavior at runtime. By integrating seamlessly with major AI frameworks such as LangChain, LlamaIndex, LiteLLM, and the OpenAI SDK, Langfuse eliminates the guesswork from debugging complex agent execution trees. Developers can monitor production cost metrics, identify hallucinated responses, and run rigorous continuous evaluation suites on live traffic.

The platform architecture features asynchronous tracing hooks that introduce negligible latency overhead to live user interactions. Teams can set up human-in-the-loop scoring, programmatic assertion checks, and automated LLM-as-a-judge evaluations to benchmark prompt iterations against golden test datasets. Langfuse is fully open-source with MIT licensing, allowing organizations with strict data governance policies to self-host the complete observability stack on private Kubernetes clusters or AWS VPCs while maintaining identical enterprise dashboard ergonomics.