Braintrust

Braintrust is an observability and evaluation platform for teams running AI agents in production. It is best for builders who want to connect live traces to systematic testing and prompt iteration. Its joined-up workflow is the draw; the Starter caps and Pro usage charges make growth costs worth watching.

Overview

Braintrust pairs inspection of production traces with experiments on datasets, prompts, and models. Teams can track latency, cost, and quality, then score outputs with LLMs, code, or human reviewers. That connection is useful when a team needs to turn observed agent behavior into repeatable evaluations. Teams looking only for a standalone testing tool may find the broader production workflow unnecessary.

Key features

Tracing covers agent traces and tool calls, while discovery tools help identify patterns in production activity for investigation. This gives teams a path from noticing behavior to examining it, without claiming that the platform automatically diagnoses or fixes the cause.

Evaluation experiments compare prompts and models against datasets, with scoring by LLMs, code, or people. Custom metrics, safety evaluations, human review workflows, prompt versioning, and CI/CD integration support teams that want quality checks to accompany prompt changes. Starter allows one human review score per project; Pro and Enterprise remove that limit with unlimited human review scores.

The Loop agent can run evaluations, generate test cases, and iterate on prompts autonomously. Native SDKs for Python, TypeScript, Go, Ruby, C#, and more, plus a framework-agnostic approach, suit teams using varied stacks. Its MCP server connects coding agents to Braintrust's AI stack for querying logs, running evaluations, and updating prompts from an IDE.

Braintrust states that it is SOC 2 Type II certified and GDPR and HIPAA compliant. SSO, RBAC, and hybrid deployment options address organizational controls; Enterprise adds custom retention and S3 trace export.

Pricing

Braintrust uses a freemium model. Starter costs nothing, billed monthly, and includes 1 GB of processed data, 10,000 scores, 14-day retention, unlimited users, unlimited projects, and unlimited datasets. That is a meaningful starting allowance for teams evaluating the workflow, but the one-human-review-score-per-project limit and short retention constrain more sustained review and analysis.

Pro costs $249 a month and includes $100 credits + tok rates, 5 GB processed data, 50k scores, 30-day retention, custom charts, environments, priority support, and RBAC. Beyond the included quotas, processed data costs +$3/GB, scores cost $1.50/1k, and retention costs $0.50/GB/mo. Unlimited human review scores make Pro a better fit for teams using people to assess outputs, but the overages mean higher activity can raise the bill.

Enterprise has custom pricing and includes custom retention and export, RBAC, premium support, and on-prem or hosted deployment. It suits organizations that need those deployment or data controls rather than a fixed public tier. Support progresses from community on Starter to priority on Pro and a shared Slack channel on Enterprise.

Platforms

Braintrust is available as an API, a web product, and self-hosted software. The combination supports teams choosing between integrating it into their own stack and using the hosted product; Enterprise also offers on-prem or hosted deployment.

Who it's for

Braintrust is aimed at teams running agents in production, from early-stage builders to enterprise organizations. It is strongest for teams that will use trace inspection, dataset evaluations, and prompt iteration together. A team that needs only a small local evaluation setup may have little reason to pay for the wider observability workflow.

Pros and cons

• Pro: Connects production tracing to dataset-based experiments, so teams can investigate behavior and evaluate changes in one platform.
• Pro: Supports LLM, code, and human scoring, with unlimited human review scores on paid plans.
• Pro: Offers multiple SDKs, API and self-hosted options, and enterprise security and deployment controls.
• Con: Starter's 1 GB of data, 10,000 scores, 14-day retention, and one human score per project may be limiting for sustained production use.
• Con: Pro's additional data, score, and retention charges make usage growth a budgeting consideration.

Alternatives

Choose Promptfoo if its free Community plan's 10k red-team probes per month, LLM evaluation features, provider integrations, and local or self-hosted runs better match a testing-focused workflow. Langfuse is another freemium API, self-hosted, and web option, with a Hobby plan that includes 50k units per month, 30 days of data access, two users, and community support via GitHub.

Vellum, PromptHelm, Agenta, ChainForge, HoneyHive, and Maxim AI are other alternatives to compare.

For broader comparisons, see AI Prompt Management Software, LLM Evaluation Tools, AI LLM Observability Tools, AI Agent Observability Tools, AI LLM Evaluation Tools, and AI Agent Evaluation Tools.

Verdict

Braintrust is a strong choice for production agent teams that want to move from trace inspection to structured evaluation and prompt iteration without splitting those jobs across tools. Its broad scoring and integration options are compelling, but teams should weigh Starter's caps and Pro's metered overages against their expected activity. Look elsewhere if your needs stop at lightweight local evaluation.