Keywords AI

Braintrust vs Langfuse

Compare Braintrust and Langfuse side by side. Both are tools in the Observability, Prompts & Evals category.

Quick Comparison

	Braintrust	Langfuse
Category	Observability, Prompts & Evals	Observability, Prompts & Evals
Pricing	Freemium	Open Source
Best For	AI teams who need a unified platform for logging, evaluating, and improving LLM applications	Teams who want open-source LLM observability they can self-host and customize
Website	braintrust.dev	langfuse.com
Key Features	Real-time LLM logging and tracing Built-in evaluation framework Prompt playground Dataset management Human review workflows	Open-source LLM observability Detailed trace and span tracking Prompt management Evaluation scoring Self-hosted and cloud options
Use Cases	Iterating on prompts with real production data Running evaluations across model versions Building golden datasets from production traffic Human-in-the-loop review of LLM outputs Cost and latency optimization	Self-hosted LLM monitoring Open-source tracing for AI applications Prompt versioning and management Cost tracking across providers Community-driven observability

When to Choose Braintrust vs Langfuse

Choose Braintrust if you need

Iterating on prompts with real production data
Running evaluations across model versions
Building golden datasets from production traffic

Pricing: Freemium

Choose Langfuse if you need

Self-hosted LLM monitoring
Open-source tracing for AI applications
Prompt versioning and management

Pricing: Open Source

About Braintrust

Braintrust is an end-to-end AI product platform trusted by companies like Notion, Stripe, and Vercel. It combines logging, evaluation datasets, prompt management, and an AI proxy with automatic caching and fallback. Braintrust's evaluation framework helps teams measure quality across prompt iterations with customizable scoring functions.

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About Langfuse

Langfuse is an open-source LLM observability platform that provides tracing, analytics, prompt management, and evaluation for AI applications. It captures detailed traces of LLM calls, supports custom scoring, and integrates with LangChain, LlamaIndex, Vercel AI SDK, and raw API calls. Langfuse can be self-hosted for data privacy or used as a managed cloud service. Its open-source model and generous free tier make it popular with startups and developers.

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What is Observability, Prompts & Evals?

Tools for monitoring LLM applications in production, managing and versioning prompts, and evaluating model outputs. Includes tracing, logging, cost tracking, prompt engineering platforms, automated evaluation frameworks, and human annotation workflows.

Browse all Observability, Prompts & Evals tools →