Capability · Comparison
Braintrust vs LangSmith
Braintrust and LangSmith both do LLM evaluation and production tracing, but they emerged from different corners of the ecosystem. Braintrust is framework-agnostic and eval-first — its mental model is 'write tests for your LLM output'. LangSmith is the LangChain team's tracing and eval platform — deeply integrated into LangChain/LangGraph and excellent when that's your stack. The decision usually comes down to how tied you are to LangChain.
Side-by-side
| Criterion | Braintrust | LangSmith |
|---|---|---|
| Primary integration | Framework-agnostic SDK + OpenTelemetry | LangChain / LangGraph + generic tracing |
| Evaluation | First-class — datasets, scorers, CI integration | First-class — datasets, custom evaluators |
| Playground / prompt iteration | Strong — side-by-side diffs, regression tests | Strong — hub, versioning, experiment comparisons |
| Tracing in production | Yes — low-overhead background logging | Yes — integrates with LangChain callbacks |
| Language SDKs | TypeScript, Python | TypeScript, Python |
| Self-hosting | Enterprise SKU available | Self-hosted offering (enterprise tier) |
| Pricing model (as of 2026-04) | Usage-based with free hobby tier | Usage-based with free tier |
| Best fit stack | OpenAI/Anthropic SDKs directly, Vercel AI, custom | LangChain, LangGraph, LangServe |
Verdict
If your agents live in LangChain or LangGraph, LangSmith is the lowest-friction choice — tracing and eval are one import away. If your stack is framework-free or mixed (OpenAI SDK here, Anthropic SDK there, a sprinkle of custom code), Braintrust's framework-agnostic model and strong regression testing tend to feel cleaner. Many teams end up choosing based on their first framework decision and sticking with it.
When to choose each
Choose Braintrust if…
- You're not on LangChain / LangGraph.
- Eval-first workflow is important — you write tests for LLM output.
- You want CI-friendly regression dashboards for prompts.
- You have heterogeneous frameworks across services.
Choose LangSmith if…
- You're building on LangChain or LangGraph.
- You want zero-config tracing from those frameworks.
- You use LangChain Hub for prompt versioning.
- You may adopt LangServe or other LangChain-native deploy tools.
Frequently asked questions
Can I use either with OpenAI directly (no framework)?
Yes — both have framework-free SDKs. Braintrust is slightly more ergonomic for this case; LangSmith requires a bit more setup but works fine.
Which has better eval features?
They're close. Braintrust's eval UX and CI integration feel a touch more polished; LangSmith's experiment comparison is excellent. Pick by ecosystem, not eval features.
Is there OpenTelemetry support?
Yes, both support OpenTelemetry as of 2026-04, which makes moving between them (or to a self-hosted alternative) easier than it used to be.
Sources
- Braintrust — accessed 2026-04-20
- LangSmith — accessed 2026-04-20