Braintrust

Braintrust builds an observability and evaluation platform for engineering and product teams developing AI applications and agents. Teams can inspect prompts, responses and tool calls, track latency and cost, compare models, and score outputs with code, language models or human reviewers. Production traces become versioned evaluation datasets for testing changes against real failures. Topics discovers patterns across production traces, while Loop generates prompts, scorers and datasets to help teams improve their agents.

Introduced in 2023, Braintrust was founded by CEO Ankur Goyal, who previously founded Impira and led Figma’s AI platform after Figma acquired it. Its engineering work includes Brainstore, a database built for agent traces that combines inverted indexes and columnar structures with object storage. Its phrase search uses filters based on consecutive three-word sequences to skip irrelevant storage segments, helping developers locate specific text in large trace collections. Hybrid deployment lets enterprises run the data plane on their own infrastructure.

Customers include Notion, Replit, Cloudflare, Ramp and Dropbox. In February 2026, Braintrust raised an $80 million Series B led by ICONIQ, with returning investors including Andreessen Horowitz and Greylock, at a reported $800 million valuation.