LLM Observability & Agent Tracing Platform · Vendor file

Braintrust

AI evaluation and observability platform with unlimited users, evals-first approach

Active · verified June 2026

Categories Braintrust serves

The B4 Index places Braintrust in 3 categories. Each category page lays out the build-versus-buy considerations for that decision.

LLM Observability & Agent Tracing Platform Primary Free tier. Pro $249/month (unlimited users).

AI Model Evaluation (Evals) Platform Primary Free tier; Pro $249/mo; Enterprise custom

Prompt Management & Engineering Platform Free tier; Pro $249/mo; enterprise custom

Braintrust compared

Braintrust vs Langfuse Braintrust vs LangSmith

The B4 Index scores every software category on two axes, strategic differentiation and AI feasibility, to classify it Build, Buy, Bridge, or Beware. Vendor facts here are independent of that call. See the full methodology.