Arize Phoenix vs Confident AI (DeepEval)
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
AI tool · Open source
An open-source tool for tracing, evaluating and experimenting with LLM and agent applications, built on OpenTelemetry.
AI tool · Freemium
The cloud platform behind DeepEval, an open-source framework for unit-testing LLM outputs with ready-made metrics.
The short answer
Choose Arize Phoenix if you need…
- Local debugging of LLM traces
- OpenTelemetry-based stacks
Choose Confident AI (DeepEval) if you need…
- Pytest-style LLM tests
- RAG evaluation metrics
Side-by-side
| Arize Phoenix | Confident AI (DeepEval) | |
|---|---|---|
| Type | Prompting · Evaluation & observability | Prompting · Evaluation & observability |
| Price | Open source | Freemium |
| Platforms | Self-hosted, Web, API | Web, API, CLI |
| Works with | LangChain, LlamaIndex, OpenAI | LangChain, LlamaIndex |
| Hands-on tested by us | Not yet | Not yet |
| Last checked | 2026-10-29 | 2026-10-29 |
What each one is
Arize Phoenix
An open-source tool for tracing, evaluating and experimenting with LLM and agent applications, built on OpenTelemetry. Standards-based and free to run locally. Enterprise features live in Arize's paid platform.
Confident AI (DeepEval)
The cloud platform behind DeepEval, an open-source framework for unit-testing LLM outputs with ready-made metrics. Easy to drop into Python test suites. LLM-judged metrics can be noisy, so calibrate them against human review.
Best for
Arize Phoenix
- Local debugging of LLM traces
- OpenTelemetry-based stacks
Confident AI (DeepEval)
- Pytest-style LLM tests
- RAG evaluation metrics
Strengths
Arize Phoenix
- OpenTelemetry tracing
- LLM-as-judge evals
- Prompt playground
- Datasets and experiments
Confident AI (DeepEval)
- Open-source DeepEval metrics
- Test datasets
- Regression reports
- Tracing
Frequently asked questions
What is the difference between Arize Phoenix and Confident AI (DeepEval)?
Arize Phoenix: An open-source tool for tracing, evaluating and experimenting with LLM and agent applications, built on OpenTelemetry. Confident AI (DeepEval): The cloud platform behind DeepEval, an open-source framework for unit-testing LLM outputs with ready-made metrics. Arize Phoenix suits local debugging of llm traces, while Confident AI (DeepEval) suits pytest-style llm tests.
Are Arize Phoenix and Confident AI (DeepEval) free?
Arize Phoenix: Open source. Confident AI (DeepEval): Freemium.
What are other alternatives to Arize Phoenix and Confident AI (DeepEval)?
Other options people compare them with include Langfuse, LangSmith, Opik, promptfoo, Braintrust.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.