Arize Phoenix

Open-source LLM and vector observability platform with built-in evaluation and debugging.

Overview

Phoenix provides end-to-end tracing for LLM applications, vector store analytics, and dataset management. It features a lightweight Python SDK and a web UI for inspecting spans, filtering traces, and running evaluation metrics directly on production data.

Best for

• vector-db debugging
• LLM trace inspection
• open-source stack preference

Trade-offs

What XeroHack pre-wires

When you pick Arize Phoenix in the interview, the engine emits these files into your scaffold:

• phoenix auto-instrumentation
• vector similarity search visualization
• RAG evaluation templates