The Stack · Observability & evals (managed) API

Braintrust

Eval-first AI platform unifying evaluations, tracing/logging and prompt playground for shipping quality AI products.

API keyFreemium🔵 agent: self serve instant key

Get API key → instant key, usually no card Docs Website

CategoryObservability & evals (managed)

TypeAPI service

Authapi-key

PricingFreemium

Agent signup🔵 self serve instant key

SDKsPython, TypeScript, Go, REST

Pricing: Free Starter: 1 GB processed data, 10k scores, 14-day retention; Pro $249/mo (5 GB, 50k scores); Enterprise custom. No per-seat charge.

🔵 Agents: self serve instant key

Instant self-serve — free signup gives a key immediately (a human unblocks an agent in under 2 minutes).

Sign up free with no credit card and generate an API key from the dashboard. Ships a mature MCP server for IDE-native trace/eval querying (Cursor, Claude Code, VS Code).

Braintrust — Eval-first AI platform unifying evaluations, tracing/logging and prompt playground for shipping quality AI products.
Website: https://www.braintrust.dev
Docs: https://www.braintrust.dev/docs
Get a key: https://www.braintrust.dev/signup
Agent signup: self serve instant key — Sign up free with no credit card and generate an API key from the dashboard. Ships a mature MCP server for IDE-native trace/eval querying (Cursor, Claude Code, VS Code).
Auth: api-key
Pricing: freemium — Free Starter: 1 GB processed data, 10k scores, 14-day retention; Pro $249/mo (5 GB, 50k scores); Enterprise custom. No per-seat charge.
Full record: https://dreaming.press/api/tools/braintrust.json

Machine record: /api/tools/braintrust.json

Quickstart

# pip install braintrust autoevals ; export BRAINTRUST_API_KEY=...
from braintrust import Eval
from autoevals import Levenshtein

Eval(
    "my-project",
    data=lambda: [{"input": "Hi", "expected": "Hello"}],
    task=lambda text: text.replace("Hi", "Hello"),
    scores=[Levenshtein],
)

python · full docs →

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Braintrust FAQ

What is Braintrust?

Braintrust is Eval-first AI platform unifying evaluations, tracing/logging and prompt playground for shipping quality AI products. It's in the Observability & evals (managed) category of the dreaming.press tool directory.

Is Braintrust free?

Braintrust is freemium — free to start, paid plans for scale. Free Starter: 1 GB processed data, 10k scores, 14-day retention; Pro $249/mo (5 GB, 50k scores); Enterprise custom. No per-seat charge..

Can an AI agent sign up for Braintrust automatically?

Almost — signup is instant and self-serve (a free key with no sales call), so a human can unblock an agent in under two minutes. Sign up free with no credit card and generate an API key from the dashboard. Ships a mature MCP server for IDE-native trace/eval querying (Cursor, Claude Code, VS Code)..

Does Braintrust have an MCP server?

Braintrust does not publish an official MCP server as of our last check.

Is Braintrust open source?

Braintrust is a hosted API service, not an open-source project.

What languages does Braintrust support?

Braintrust offers Python, TypeScript, Go, REST.