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Braintrust vs LangSmith
Trust Score comparison · March 2026
Signal Comparison
12k / wknpm downloads2.5M / wk
120 commitsCommits (90d)220 commits
1.2k ★GitHub stars3.5k ★
10 q'sStack Overflow200 q's
MediumCommunityHigh
BraintrustLangSmith
Key Differences
| Factor | Braintrust | LangSmith |
|---|---|---|
| License | Proprietary | Proprietary |
| Language | TypeScript / Python | TypeScript / Python |
| Hosted | Self-hosted | Self-hosted |
| Free tier | — | — |
| Open Source | — | — |
| TypeScript | ✓ | ✓ |
Pick Braintrust if…
- Systematic eval-driven development — score outputs across test datasets
- You want a managed product with a polished eval UI
- Running A/B prompt experiments with statistical rigor
Pick LangSmith if…
- Your app is built on LangChain or LangGraph — integration is seamless
- You need prompt management and dataset-driven evaluations
- Team wants a managed cloud with minimal setup
Side-by-side Quick Start
Braintrust
import * as braintrust from 'braintrust';
const experiment = braintrust.init('my-project', {
apiKey: process.env.BRAINTRUST_API_KEY,
experiment: 'gpt-4o-baseline',
});
experiment.log({
input: 'What is 2+2?',
output: '4',
expected: '4',
scores: { accuracy: 1.0 },
});LangSmith
import { Client } from 'langsmith';
const client = new Client({ apiKey: process.env.LANGSMITH_API_KEY });
// Auto-traces when LANGCHAIN_TRACING_V2=true is set
// Or manually:
const run = await client.createRun({
name: 'my-llm-call',
run_type: 'llm',
inputs: { prompt: 'Hello' },
});Community Verdict
Based on upvoted notes🏆
LangSmith wins this comparison
Trust Score 80 vs 70 · 10-point difference
LangSmith leads on Trust Score with stronger signal data across downloads and community health. That said, the other tool is worth considering if your use case matches its specific strengths above.