Braintrust vs Opik
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
AI tool · Freemium
An evaluation and observability platform for scoring prompts and models against datasets and monitoring production.
AI tool · Open source
Comet's open-source platform for logging, evaluating and monitoring LLM apps, including prompt optimisation.
The short answer
Choose Braintrust if you need…
- Systematic evals before shipping
- Comparing prompt versions with scores
Choose Opik if you need…
- Open-source tracing and evals
- Automated prompt optimisation
Side-by-side
| Braintrust | Opik | |
|---|---|---|
| Type | Prompting · Evaluation & observability | Prompting · Evaluation & observability |
| Price | Freemium | Open source |
| Platforms | Web, API | Web, Self-hosted, API |
| Works with | OpenAI, Anthropic, Vercel | LangChain, OpenAI |
| Hands-on tested by us | Not yet | Not yet |
| Last checked | 2026-10-29 | 2026-10-29 |
What each one is
Braintrust
An evaluation and observability platform for scoring prompts and models against datasets and monitoring production. Fast, well-designed eval loop. Getting value means investing in good datasets and scorers.
Opik
Comet's open-source platform for logging, evaluating and monitoring LLM apps, including prompt optimisation. Generous open-source feature set. Younger than some rivals, so expect rough edges.
Best for
Braintrust
- Systematic evals before shipping
- Comparing prompt versions with scores
Opik
- Open-source tracing and evals
- Automated prompt optimisation
Strengths
Braintrust
- Experiments with scorers
- Prompt playground
- Logging and tracing
- Datasets
Opik
- Tracing and logging
- LLM-as-judge metrics
- Prompt library
- Agent optimiser
Frequently asked questions
What is the difference between Braintrust and Opik?
Braintrust: An evaluation and observability platform for scoring prompts and models against datasets and monitoring production. Opik: Comet's open-source platform for logging, evaluating and monitoring LLM apps, including prompt optimisation. Braintrust suits systematic evals before shipping, while Opik suits open-source tracing and evals.
Are Braintrust and Opik free?
Braintrust: Freemium. Opik: Open source.
What are other alternatives to Braintrust and Opik?
Other options people compare them with include promptfoo, Helicone, W&B Weave, Langfuse, Arize Phoenix.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.