Braintrust
observabilityBraintrust is an LLM observability and evaluation platform that treats AI quality as a release-level concern — combining production tracing, CI-integrated evaluation, prompt experimentation, and statistical regression detection in a single platform. It's the most evaluation-forward LangSmith alternative for teams that want to gate deployments on quality scores.
The Core Idea
Most observability tools tell you what happened. Braintrust closes the loop: it captures traces, runs evaluations against them, and lets you block releases in CI if quality regresses. The workflow mirrors how mature engineering teams treat test coverage — not as a dashboard to check, but as a gate in the deployment pipeline.
Key Capabilities
- Production tracing: Full spans across multi-step LLM workflows — inputs, outputs, tool calls, metadata, and cost. Live request flows with drill-down into individual traces
- Experiment runner: Compare prompts side-by-side against datasets, score with LLMs, code, or humans, and catch regressions before they ship
- CI integration: Run eval suites in CI and fail the build if pass rates drop — the same way unit tests work
- Brainstore: Purpose-built storage for AI observability — query millions of traces quickly
- AI-assisted iteration: Built-in agent that can generate test cases, run evaluations, and iterate on prompts autonomously
Getting Started
pip install braintrust
import braintrust
tracer = braintrust.init_logger(project="my-agent")
with tracer.start_span("llm-call") as span:
result = client.messages.create(...)
span.log(input=prompt, output=result.content[0].text)
Pricing
| Tier | Spans | Eval runs | Retention |
|---|---|---|---|
| Free | 1M | 10k | 14 days |
| Pro | Unlimited | Unlimited | 1 month |
| Enterprise | Custom | Custom | Custom |
Pro is $249/month. SOC 2 Type II, GDPR compliant, HIPAA available.
Key Characteristics
| Property | Value |
|---|---|
| License | Proprietary SaaS |
| Provider | Braintrust Data, Inc. |
| Website | braintrust.dev |
| Docs | braintrust.dev/docs |