Braintrust
The best pure evaluation product here, and worth saying first.
Open-source AI infrastructure
Best LLM Evaluation Platforms in 2026
Five evaluation platforms compared on the questions that decide adoption: whether self-hosting is gated by tier, how pricing scales with evaluation volume, and whet…
Langfuse
MIT core, plus an enterprise licence over ee/. 33,900+ stars. ClickHouse-owned since January 2026.
Opik
The largest community of the genuinely-clean-licence options, and actively developed. Self-hosting gives you all features including tracing and evaluation, minus user management. So you lose RBAC and multi-user administration, not evaluation capability. That is a meaningfully better deal than gating retention or masking.
OpenLIT
The lightest thing here by a distance: SDK to OpenTelemetry Collector to ClickHouse, and that is the whole architecture. Evaluations are one part of a broader Apache-2.0 project that also covers LLM observability, GPU monitoring, guardrails, prompt management and a secrets vault.
Everstack
Datasets, scorers, LLM judges, human annotation queues and regression analysis, self-hosted by default at any tier under one Apache-2.0 licence with no enterprise directory.
The three questions
| Platform | Self-hosting | | --- | --- | | Braintrust | Enterprise only | | Langfuse | Yes, minus nine gated features | | Opik | Yes, minus user management | | OpenLIT | Yes, the only distribution model | | Everstack | Yes, at any tier |