Phoenix

Phoenix is an open-source tool designed for AI developers and ML teams to trace, evaluate, and optimize large language model (LLM) applications in real time. It provides interactive tracing, evaluations, annotations, prompt engineering tools, clustering/visualization, and transparent integrations using OpenTelemetry. Phoenix is both highly flexible and vendor-agnostic, serving as a comprehensive framework for observability, debugging, and fine-tuning of LLM-powered workflows.