PHOENIX

Summary from the TLDR Data newsletter

Phoenix is a self-hosted, open-source AI observability platform for tracing, evaluating, and debugging LLM applications. It captures OpenTelemetry traces; offers retrieval and response evaluations, versioned datasets, and experiments; and supports prompt testing and replay. Framework- and provider-agnostic instrumentation makes it useful for teams that need to diagnose agent behavior and measure changes before production.