Arize Phoenix

Arize Phoenix is a source-available tool for observing and evaluating AI applications. Developers can run it locally or self-host it to inspect model calls, retrieval, and tool execution. Phoenix combines traces with evaluations, datasets, and prompt experiments for investigating quality problems.

Key Highlights

• OpenTelemetry and OpenInference instrumentation
• Traces across model, retrieval, and tool steps
• Code, LLM, and human evaluation signals
• Prompt versions, playgrounds, and span replay
• Local and self-hosted deployment under ELv2

What Makes It Different

Phoenix provides a local or self-hosted workflow built on standard telemetry formats. Developers can trace a failing run, group relevant examples into a dataset, and compare an updated prompt or application version against the same inputs. Arize AX is the separate managed enterprise platform from the same vendor.

Features & Capabilities

Instrument supported frameworks and providers to send traces over OpenTelemetry. Phoenix exposes execution spans so developers can inspect responses, retrieved context, and tool behavior. Human annotations and automated evaluations attach quality signals to those runs.

The Prompt Playground compares prompts and models, while span replay revisits individual model calls with changed inputs. Datasets and experiments let teams test revisions against repeatable cases. Self-hosting also makes the team responsible for its deployment, storage, upgrades, and access configuration.

User Ratings and Testimonials

Arize features comments from developers and AI practitioners about Phoenix's tracing and evaluation workflow. Judge it with your own application: trace a retrieval failure, test an evaluator, and compare a prompt revision on representative examples. Evaluation quality depends on the chosen criteria and data; a dashboard score is not a guarantee of correct answers.

Pricing & Value

• Local or self-hosted Phoenix: no software subscription fee for use permitted by the Elastic License 2.0.

Infrastructure and external model calls remain separate costs. ELv2 restricts offering Phoenix itself as a hosted or managed service. Review those license terms for your intended use. Managed Arize AX has its own product and pricing.