Best Arize Phoenix alternatives
5 tools developers use instead of Arize Phoenix, ranked by popularity. 5 offer a free plan and 3 are open source. Updated October 2026.
-
Open-source LLM observability platform for tracing, evaluating, and debugging prompts and agent runs, self-hostable or available as a managed cloud service.
-
Weights & Biases toolkit for tracing, evaluating and monitoring LLM applications, with automatic call logging and scorers.
-
Open-source LLM observability proxy that sits between your app and a model provider, logging requests, costs, and latency with a one-line integration change.