# Best free Braintrust alternatives

9 free alternatives to Braintrust and 0 more. Braintrust is free tier + paid.

## Alternatives

- [Arize Phoenix](https://aitools.flocci.in/tool/arize-phoenix) — Free — Fully open-source, self-hostable with zero setup via `uvx` (pip/conda also supported)
- [Google Stax](https://aitools.flocci.in/tool/google-stax) — Free — Build evals with human raters or LLM autoraters on your own data
- [Laminar](https://aitools.flocci.in/tool/laminar) — Free — Open-source observability and evals platform for AI agents (Apache-2.0)
- [Langfuse](https://aitools.flocci.in/tool/langfuse) — Freemium — Fully open-source and self-hostable for free via Docker Compose/Kubernetes, not just a hosted SaaS
- [Promptfoo](https://aitools.flocci.in/tool/promptfoo) — Freemium — Open-source CLI/library for evaluating prompts, models and RAG pipelines side by side, runs in CI
- [W&B Weave](https://aitools.flocci.in/tool/w-b-weave) — Freemium — Agent-native tracing model with sessions, steps, tools and sub-agents as first-class concepts (not generic spans)
- [Opik (Comet)](https://aitools.flocci.in/tool/opik-comet) — Freemium — Open-source LLM tracing, evaluation and prompt-optimization platform (Apache-2.0)
- [LangSmith](https://aitools.flocci.in/tool/langsmith) — Freemium — Tracing, evaluation datasets and prompt playground for LLM apps and agents
- [DeepEval](https://aitools.flocci.in/tool/deepeval) — Free — Open-source LLM evaluation framework with pytest-style tests and 50+ metrics

## FAQ

### What is the best free alternative to Braintrust?

Arize Phoenix is the closest free alternative to Braintrust: same LLM Eval & Observability sub-category, and it is free. Fully open-source, self-hostable with zero setup via `uvx` (pip/conda also supported)

### Are there free Braintrust alternatives?

Yes — 9 of the 9 alternatives listed here are free or freemium: Arize Phoenix, Google Stax, Laminar, Langfuse, Promptfoo. None of them are paid-only.

### Is Braintrust free?

Braintrust is free tier + paid. There is a free tier you can work in, with paid plans above it.

### How were these Braintrust alternatives chosen?

They are the other tools in LLM Eval & Observability, then the rest of AI Models & Local Execution, ordered free tiers first and capped at 9. There is no sponsorship and no paid placement in that ordering — only the pricing tier decides.

## Related

- [Braintrust](https://aitools.flocci.in/tool/braintrust)
- [LLM Eval & Observability](https://aitools.flocci.in/category/ai-models-local-execution/llm-eval-observability)
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Source: Flocci AI Tools — https://aitools.flocci.in/alternatives/braintrust

Facts last verified: October 2026