Braintrust

Braintrust is an end-to-end platform for evaluating, observing, and iterating on LLM applications, combining evals, a prompt playground, tracing/observability, and datasets.

Braintrust is an AI observability and evaluation platform for building quality AI products. Teams use it to run evals and experiments against real datasets, compare prompts and models side by side in a prompt playground, and score outputs with LLM judges, code, or humans. Its observability layer traces every LLM call and tool call, searches across millions of logs, and tracks latency, cost, and quality in real time, while Datasets turn production traces into regression tests. The platform also ships Autoevals (a library of prebuilt scorers) and Loop, an AI assistant that suggests improved prompts, scorers, and datasets. Founded in 2023 by Ankur Goyal and based in San Francisco, Braintrust has raised roughly $124M in total, including an $80M Series B led by ICONIQ (with Andreessen Horowitz, Greylock, and Elad Gil) announced in early 2026. It offers SDKs in TypeScript, Python, Go, and Ruby.

Category

Developer Tools

Pricing

Freemium, Subscription, Usage-based, Enterprise

Target Market

AI engineering teams, Startups, Enterprise

Founded

2023

Headquarters

San Francisco, USA

• ✓
  Evals & Experiments

  Run experiments against real datasets and score outputs with LLM judges, code, or humans.

• ✓
  Prompt Playground

  Compare prompts and models side by side and iterate on evaluations visually, no code required.

• ✓
  Observability & Tracing

  Inspect every trace and tool call, search millions of logs, and track latency, cost, and quality in real time.

• ✓
  Datasets

  Convert production traces into evaluation datasets and build regression tests from real failures.

• ✓
  Autoevals

  Library of prebuilt scorers (heuristic, statistical, and model-graded) for evaluating AI outputs.

• ✓
  Loop

  AI assistant that generates improved prompts, scorers, and datasets from a described optimization goal.

• •
  Pre-ship regression testing

  Evaluate prompt and model changes against datasets to catch regressions before deployment.

• •
  Production monitoring

  Trace live LLM app behavior and track quality, cost, and latency with online scoring.

• •
  Collaborative prompt iteration

  Use the playground to compare models and prompts and refine them as a team.

Free Starter tier requires no credit card and includes $10 credits. Pro is $249/month (with 6-12 months free for qualifying startups). Usage-based add-ons apply across tiers, e.g. processed data ($4/GB Starter, $3/GB Pro) and scores ($2.50 per 1,000 Starter, $1.50 per 1,000 Pro); Enterprise is custom.