Braintrust

Braintrust is an eval-first LLM evaluation and observability platform that unifies datasets, experiments, LLM/code/human scorers, a prompt playground, production logging, human review, and CI/CD gating. It emphasizes turning production traces into evaluation datasets and catching quality regressions before deploy. It is well-funded and actively developed but source-available rather than open source, with self-hosting limited to Enterprise.

Braintrust focuses on making evaluation a first-class part of AI development. It gives teams datasets and experiments with statistical significance testing, LLM/code/human scorers, and a powerful playground for comparing prompts and models side by side. Production traces can be turned into evaluation datasets, closing the loop between what ships and how it is measured. A distinguishing strength is its CI/CD integration: Braintrust can fail builds via GitHub Actions when quality regressions are detected, bringing software-engineering rigor to prompt and model changes. It also offers an AI Proxy for logging, caching, and provider fallbacks, plus TypeScript and Python SDKs. Braintrust is not open source; self-hosting is available only on Enterprise and uses a hybrid model where the customer runs the data plane while Braintrust hosts the control plane. Pricing is usage-based on processed data and scores rather than per seat, which keeps user counts unlimited but makes costs scale with trace and evaluation volume.