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LangSmith vs Braintrust
Trust Score comparison · March 2026
Signal Comparison
2.5M / wkPyPI downloads12k / wk
220 commitsCommits (90d)120 commits
3.5k ★GitHub stars1.2k ★
200 q'sStack Overflow10 q's
HighCommunityMedium
LangSmithBraintrust
Key Differences
| Factor | LangSmith | Braintrust |
|---|---|---|
| License | Proprietary | Proprietary |
| Language | TypeScript / Python | TypeScript / Python |
| Hosted | Self-hosted | Self-hosted |
| Free tier | — | — |
| Open Source | — | — |
| TypeScript | ✓ | ✓ |
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
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
Side-by-side Quick Start
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' },
});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 },
});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.