Braintrust

Evaluate AI applications, compare prompts and manage test datasets.

evalsprompts

Websitebraintrust.dev

CategoryAI & machine learning

PricingFreemium

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ABOUT

What is Braintrust?

Braintrust provides an evaluation and observability layer for LLM applications. It lets you run scored experiments across different prompt versions and model configurations, track regressions and compare outputs side by side. The platform integrates via a thin SDK wrapper around your existing LLM calls, with no major code rewrites required.

BEFORE YOU SIGN UP

What you should know

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Side-by-side prompt comparisonRun the same dataset through multiple prompt versions or models simultaneously and compare outputs, scores and latency in a single view.

✓

Minimal integration overheadWrap existing LLM calls with the Braintrust SDK in a few lines. Works with OpenAI, Anthropic, Google and any OpenAI-compatible endpoint.

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Primarily a cloud productUnlike Langfuse or Comet Opik, Braintrust does not have a self-hosted open-source edition. All data goes through Braintrust infrastructure.

10k score limit on free tierEach scored evaluation counts toward the monthly limit. Large test suites or frequent CI runs can exhaust the free quota faster than expected.

COMMUNITY

From the forums

The LLM engineering community on Twitter/X and in AI newsletters positions Braintrust alongside Langfuse and Comet Opik as the three go-to evals platforms. Users highlight the clean UI for reviewing experiment results and the dataset management features. The main criticism is that the free tier's 10k score limit per month can be reached quickly during active development with large test suites.

— Community sentiment

💬Discuss on Reddit ↗

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ABOUT US

Honest, independent, no fluff.

No paid placements. Just a clear look at what this does, what it costs, and what to know before you commit.

FAQ

Questions, answered.

What is a score in Braintrust?＋

A score is a numeric or categorical evaluation result attached to a single model output. Scores can be from automated LLM judges, heuristic functions or human annotations.

How does Braintrust differ from Langfuse?＋

Both cover evals and tracing. Braintrust has a stronger focus on experiment comparison and prompt management. Langfuse has a more mature observability story and a self-hosted open-source option. The choice often comes down to whether you need self-hosting.