Braintrust review

Q: How do I install Braintrust?

Run npm install braintrust autoevals. The install section above has the other options from the project's README.

Braintrust is a platform for evaluating and shipping AI products, with JavaScript/TypeScript SDKs for logging, tracing, evals, and a CLI.

Updated Nov 1, 2026. Review written Oct 22, 2026 from the project's own sources; usage data refreshed every Monday.

TL;DR

Braintrust is an AI observability platform for tracing production, running evals, and catching regressions before they reach users. This repository holds its JavaScript/TypeScript SDKs and integrations, aimed at teams building AI agents and products. It pairs code-defined evals with production tracing, plus integrations for OpenTelemetry, Temporal, and the browser.

29GitHub stars
+0new stars, week of Oct 25
~4.2Mdownloads a week, +10% vs 4-week avg
#15in Evals and observability this week

Braintrust at a glance

Category: Evals and observability
Maintained by: Braintrust (organization, @braintrustdata on GitHub)
License: Apache 2.0
Language: TypeScript, JavaScript, Makefile
Repository: github.com/braintrustdata/braintrust-sdk-javascript
Website: www.braintrust.dev
npm package: braintrust 3.39.0
PyPI package: braintrust 0.48.0
Latest release: [email protected] on GitHub, Oct 21, 2026
First published: Jul 17, 2023

What Braintrust does

Braintrust defines evals in code with a dataset, a task function, and scorers such as LevenshteinScorer from autoevals.
Braintrust traces prompts, responses, and tool calls, and tracks latency, cost, and quality in production.
Braintrust provides an OpenTelemetry span processor and compatibility helpers, including support for span customizers.
Braintrust offers a Temporal client/worker plugin and workflow interceptors for tracing workflows.
Braintrust adds application logging and console capture, plus batch tracing for the AI SDK.
Braintrust turns production traces into eval datasets so regression tests come from real failures.

How to install and start using Braintrust

With npm

npm install braintrust autoevals

Requirements

Node.js with npm to install the JavaScript/TypeScript SDK.
For braintrust/custom-views, your own @types/react for React 18 or newer.

First steps

Install the braintrust and autoevals packages with npm.
Create tutorial.eval.ts that calls Eval with data, a task, and a scorer like LevenshteinScorer.
Run the eval with your API key: BRAINTRUST_API_KEY=<YOUR_API_KEY> npx braintrust eval tutorial.eval.ts

Who Braintrust is for

TypeScript teams that want to write and run LLM evals as code.
Teams tracing AI agents in production and inspecting tool calls.
Projects already using OpenTelemetry or Temporal that need AI tracing.

Limitations to know

Braintrust's SDK sends data to the Braintrust platform and needs an API key to run evals.
Braintrust's @braintrust/langchain-js and @braintrust/openai-agents packages are deprecated in favor of integrations in the main braintrust package.
Braintrust keeps its Python SDK in a separate repository, so this repo covers JavaScript/TypeScript only.

Is Braintrust growing? Usage data

In the week of Oct 25–31, 2026, Braintrust ranked #282 on the Devtoolwatch Board and #15 in Evals and observability, with a momentum score of 34 out of 100. Its main package had about 4.2M downloads that week, +10% against its own 4-week average.

New GitHub stars per week for the last 12 weeks, from GitHub's stargazer history (today's stargazers by the week they starred).

Show the weekly numbers

New GitHub stars per week for Braintrust
Week of	New stars
Aug 9, 2026	2
Aug 16, 2026	0
Aug 23, 2026	0
Aug 30, 2026	0
Sep 6, 2026	0
Sep 13, 2026	0
Sep 20, 2026	1
Sep 27, 2026	0
Oct 4, 2026	1
Oct 11, 2026	0
Oct 18, 2026	0
Oct 25, 2026	0

On Hacker News

The rise of async AI programming, 123 points and 109 comments (Sep 11, 2025)
Llama-3.1 supports tool calls via prompting, 35 points and 4 comments (Jul 26, 2024)
Brainstore: A full-text search database on Obj Store written in Rust, 5 points and 0 comments (Mar 3, 2025)

The Board ranks tools by four signals each week: new stars, new stars for the repo's size, added downloads and download growth beyond the market. How the ranking works.

Braintrust alternatives

Other LLM evals and observability tools on the Board in the week of Oct 25–31, 2026, by momentum:

Evals and observability ranked by momentum, the week of Oct 25–31, 2026
Rank	Tool	Stars	Downloads/wk
#1	SkillSpectorSkillSpector is NVIDIA's security scanner that checks AI agent skills for vulnerabilities, malicious patterns, and supply-chain risks…	23.7k	–
#2	JudgevalJudgeval is an open-source Python SDK for tracing and evaluating LLM-powered agents with prompt-based judges and online monitoring.	1.1k	80.2k
#3	A.I.G (AI-Infra-Guard)A full-stack AI Red Teaming platform securing AI ecosystems via Agent Scan, Skills Scan, MCP scan, AI Infra scan and LLM jailbreak…	7.2k	–
#4	LangfuseLangfuse is an open source LLM engineering platform for tracing, evaluating, prompt management, and debugging LLM applications and agents.	36.8k	9.8M
#5	OpikOpik is an open-source platform from Comet for tracing, evaluating, and monitoring LLM applications, RAG systems, and AI agents.	23.1k	709.1k
#6	promptfoopromptfoo is a CLI and library for evaluating and red-teaming LLM-based apps, including prompts, agents, and RAG pipelines.	26.7k	1.2M

All LLM evals and observability tools, ranked

Recent Braintrust releases

[email protected], Oct 21, 2026
@braintrust/[email protected], Oct 19, 2026
[email protected], Oct 19, 2026
[email protected], Oct 9, 2026
[email protected], Oct 7, 2026

Braintrust FAQ

Is Braintrust free and open source?

Yes. Braintrust's source code is on GitHub (braintrustdata/braintrust-sdk-javascript) under the Apache 2.0 license, so you can use it for free. Its website also links to a pricing page (https://www.braintrust.dev/pricing) for any paid plans.

How do I install Braintrust?

Run npm install braintrust autoevals. The install section above has the other options from the project's README.

Is Braintrust still maintained?

Yes. The braintrustdata/braintrust-sdk-javascript repository was last updated on Oct 21, 2026, and the latest release, [email protected] on GitHub, came out on Oct 21, 2026.

How popular is Braintrust?

Braintrust has 29 GitHub stars as of Nov 1, 2026. It gained 0 new stars in the week of Oct 25–31, 2026, against a 12-week average of 0 a week. Its main package had about 4.2M downloads that week, +10% against its own 4-week average. That made it #15 among LLM evals and observability tools on the Devtoolwatch Board.

Braintrust vs Langfuse: how do they compare?

Braintrust and Langfuse are both tracked by Devtoolwatch as LLM evals and observability tools. Braintrust has 29 GitHub stars and Langfuse has 36.8k. In the week of Oct 25–31, 2026, Braintrust's main package had 4.2M downloads and Langfuse's had 9.8M. Langfuse is an open source LLM engineering platform for tracing, evaluating, prompt management, and debugging LLM applications and agents. Langfuse review.

Braintrust vs LangChain: how do they compare?

Braintrust and LangChain are both tracked by Devtoolwatch. Braintrust has 29 GitHub stars and LangChain has 148.8k. In the week of Oct 25–31, 2026, Braintrust's main package had 4.2M downloads and LangChain's had 41.1M. LangChain review.

What are the best alternatives to Braintrust?

Other LLM evals and observability tools on the Devtoolwatch Board in the week of Oct 25–31, 2026, by momentum: SkillSpector (#1), Judgeval (#2), A.I.G (AI-Infra-Guard) (#3), Langfuse (#4), Opik (#5). The alternatives table above has their numbers.

Does Braintrust work with Python?

Braintrust has a Python SDK on PyPI that requires Python 3.10 or newer. Its code lives in a separate Braintrust Python SDK repository, split out of this JavaScript repo.

What is the bt CLI in Braintrust?

Braintrust installs the bt CLI alongside the braintrust package. You run it with npx bt or pnpm exec bt.

How does Braintrust score eval outputs?

Braintrust scores outputs with LLMs, code, or humans. In code, you pass scorers such as LevenshteinScorer from the autoevals package to Eval.

Can Braintrust cancel long-running evals?

Braintrust supports cooperative cancellation since 3.37.0. On timeout or abort, it stops new trials, aborts hooks.signal, and waits for in-flight tasks and scorers to settle.

Sources

Braintrust README badge

Maintainers can show the tool's weekly Board rank in their README:

[![Devtoolwatch](https://index.devtoolwatch.com/badge/braintrust.svg)](https://index.devtoolwatch.com/tools/braintrust/)

How this page is made: Devtoolwatch writes each review from the project's README, releases, package metadata and website, with an AI model, then checks every claim against the source it cites and drops what the sources don't support. The numbers come from Devtoolwatch's daily GitHub snapshots, GitHub's stargazer history, and the npm and PyPI download APIs. Spotted an error? Email [email protected].