Braintrust

Braintrust is an evaluation and observability platform that helps AI engineering teams trace what their agents do, measure output quality and catch regressions before users do. Its emphasis is on evals as a daily habit: production traces flow into datasets, datasets feed experiments, and scorers grade every change to a prompt or model. An in-product assistant called Loop helps write those prompts, scorers and datasets, which lowers the effort of building a serious eval suite.

What is Braintrust used for?

Braintrust is used to replace guesswork with measurement when shipping LLM features. Typical uses include:

• Logging prompts, responses and tool calls from production agents
• Comparing prompts or models side by side on the same dataset
• Grading outputs with LLM judges, code checks or human reviewers
• Turning a bad production trace into a regression test in one click
• Finding recurring failure patterns and topics across large trace volumes
• Testing a new frontier model against existing evals before switching

Who Braintrust is best for

Braintrust suits AI engineers and product teams at companies where LLM features are core to the product and quality has to be proven, not assumed. Its named customers are software companies running AI at scale. Enterprises needing SAML SSO, a BAA or on-premise data planes can get them on Enterprise. Early hobby projects that only need a few prompt tests may not need a dedicated eval platform yet.

Braintrust pricing

As of October 2026, Braintrust Starter is free with no card required and includes $10 of model credits, 1GB of processed data, 10,000 scores and 14 days of retention, with unlimited users, projects, datasets, playgrounds and experiments. Pro costs $249 per month and includes $100 of model credits, 5GB of data, 50,000 scores, 30 days of retention, custom charts, environments, basic roles and priority support. Overage is billed per gigabyte and per thousand scores. Enterprise is custom and adds custom retention, S3 export, SAML SSO, a BAA, premium support and on-prem or hosted deployment.

Braintrust limitations

• The gap between the free tier and the $249 Pro plan is large for small teams
• Free retention is 14 days, which limits trend analysis
• It is a measurement tool, not an agent builder, so it sits beside your framework
• Usage-based data and score charges need monitoring as traffic grows

Braintrust vs alternatives

LangChain offers its own tracing and evaluation product that fits naturally if your agents are already built with LangChain. OpenAI Playground is useful for quick prompt experiments with OpenAI models but does not trace production systems or run scored experiments. Google AI Studio is similar for prototyping with Gemini models. Braintrust wins when you need framework-neutral production tracing, scored experiments and a team workflow for improving quality release after release.

Tips for getting started with Braintrust

Instrument one production endpoint and let traces collect for a few days before writing scorers, so you evaluate on real inputs. Start with a small dataset of known good and bad cases and two scorers, one automated and one human. Use Loop to draft additional scorers from plain-language goals. Run an experiment every time you change a prompt or model and keep the comparison in the project.

Braintrust FAQ

Is Braintrust free?

Yes, Braintrust has a free Starter plan with $10 of model credits, 1GB of processed data and 10,000 scores a month. The Pro plan costs $249 per month.

What is Braintrust used for?

Braintrust is used to trace AI agents in production, run evaluations on datasets, compare prompts and models, and turn real failures into regression tests.

Does Braintrust have an SDK?

Yes. Braintrust offers SDKs for Python, TypeScript, Go, Ruby and C#, along with an MCP server that connects coding agents to your evaluation data.

Is Braintrust safe to use with company data?

Braintrust states it is SOC 2 Type II certified, GDPR compliant and HIPAA compliant, and Enterprise adds SAML SSO, a BAA and hybrid deployment of its data plane.