# Braintrust

> Braintrust is an eval-first AI observability platform whose own storage engine Brainstore is proprietary and written in Rust; its open-source autoevals library is MIT-licensed, and the company raised an $80M Series B in February 2026 at a reported ~$800M valuation.

Eval-first AI observability platform with an open-source autoevals library.

- **Category:** Observability
- **License:** Proprietary (platform); autoevals is MIT
- **Language:** TypeScript (SDK)
- **Self-hosted:** No
- **GitHub stars:** 1044 (2026-10-04)
- **Repository:** https://github.com/braintrustdata/autoevals
- **Last verified:** 2026-10-04

> Caveat: Self-hosting availability is unclear: sources conflict on whether it is a general option or enterprise-only.

Source: https://agent.c8.fit/tools/braintrust/