What it is
Opik is the open-source LLM evaluation and observability product from Comet, an MLOps platform that's been operating in production since 2017. Tracing, prompt management, LLM-as-judge scoring, human annotation workflows — all the standard pieces, with stronger framework integration than most OSS competitors.
Free under Apache 2.0, with a Comet-hosted cloud option for teams that don't want to run it.
Where it shines
- Framework integrations. DSPy, AutoGen, Google ADK, and the standard LangChain/LlamaIndex set. The DSPy integration in particular is well-executed in a way most platforms haven't bothered with.
- Institutional credibility. Comet has been operating MLOps infrastructure for years. That matters for procurement teams, on-call rotations, and "will this still exist in 2 years" conversations that early-stage OSS projects can't answer the same way.
- Human annotation. A real workflow for review, scoring, and disagreement resolution — not just a UI bolted on.
Where it falls short
- Maturity gap. Opik is newer than Langfuse and some enterprise polish is still landing.
- Two-product tax. Comet (ML) and Opik (LLM) overlap in confusing ways for new users. Docs and pricing reflect that.
Bottom line
If you want OSS LLM eval and Langfuse's pace or company stage gives you pause, Opik is the most credible alternative. Existing Comet customers should adopt it before evaluating anything else.