Braintrust vs Langfuse
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
AI tool · Freemium
An evaluation and observability platform for scoring prompts and models against datasets and monitoring production.
AI tool · Open source
An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking.
The short answer
Choose Braintrust if you need…
- Systematic evals before shipping
- Comparing prompt versions with scores
Choose Langfuse if you need…
- Tracing LLM apps in production
- Self-hosted prompt management
Side-by-side
| Braintrust | Langfuse | |
|---|---|---|
| Type | Prompting · Evaluation & observability | Prompting · Evaluation & observability |
| Price | Freemium | Open source |
| Platforms | Web, API | Web, Self-hosted, API |
| Works with | OpenAI, Anthropic, Vercel | LangChain, OpenAI, LlamaIndex |
| Hands-on tested by us | Not yet | Not yet |
| Last checked | 2026-10-29 | 2026-10-29 |
What each one is
Braintrust
An evaluation and observability platform for scoring prompts and models against datasets and monitoring production. Fast, well-designed eval loop. Getting value means investing in good datasets and scorers.
Langfuse
An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking. A popular, well-documented default for observability. Self-hosting at scale needs some operational effort.
Best for
Braintrust
- Systematic evals before shipping
- Comparing prompt versions with scores
Langfuse
- Tracing LLM apps in production
- Self-hosted prompt management
Strengths
Braintrust
- Experiments with scorers
- Prompt playground
- Logging and tracing
- Datasets
Langfuse
- Traces and spans for LLM calls
- Prompt management with versions
- Evals and datasets
- Cost and latency dashboards
Frequently asked questions
What is the difference between Braintrust and Langfuse?
Braintrust: An evaluation and observability platform for scoring prompts and models against datasets and monitoring production. Langfuse: An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking. Braintrust suits systematic evals before shipping, while Langfuse suits tracing llm apps in production.
Are Braintrust and Langfuse free?
Braintrust: Freemium. Langfuse: Open source.
What are other alternatives to Braintrust and Langfuse?
Other options people compare them with include promptfoo, Helicone, W&B Weave, Arize Phoenix, LangSmith.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.