Arize Phoenix vs Prompt flow
A side-by-side comparison of two self-hosted self-hosted ai options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Arize Phoenix | Prompt flow |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 93 · Excellent | 78 · Good |
| Category | Self-Hosted AI | Self-Hosted AI |
| License | Elastic-2.0 | MIT |
| Language | Python | Python |
| Setup difficulty | Medium | Medium |
| Min. RAM | 1,024 MB | 2,048 MB |
| Deployment | docker, source | docker, source |
| GitHub stars | ★ 11,594 | ★ 11,244 |
| First released | 2023 | 2023 |
| Replaces | LangSmith, Helicone | LangSmith, Vertex AI |
What are Arize Phoenix and Prompt flow?
Arize Phoenix
Phoenix by Arize is an open-source observability platform for experimentation, evaluation and troubleshooting of LLM and ML applications. It runs as a self-hosted server collecting OpenTelemetry traces from AI apps.
- LLM tracing and spans
- Built-in evaluators
- OpenTelemetry-based
- Self-hostable
Prompt flow
Prompt flow is an open-source development toolkit from Microsoft for building, testing, and evaluating LLM-powered applications. It provides a visual flow editor, batch evaluation, and tooling to debug prompt pipelines locally.
- Visual flow authoring
- Batch evaluation runs
- Local debugging tools
- VS Code extension
Arize Phoenix vs Prompt flow: key differences
Both projects are written in Python. Licensing differs — Elastic-2.0 for Arize Phoenix versus MIT for Prompt flow. Arize Phoenix is the lighter option, starting around 1,024 MB of RAM against 2,048 MB for Prompt flow.
Why pick each one
Choose Arize Phoenix if…
- Released under the Elastic-2.0 license
- First-class Docker support for quick deployment
- Mature project with 11.6k GitHub stars
- Written in Python
Choose Prompt flow if…
- Released under the MIT license
- First-class Docker support for quick deployment
- Mature project with 11.2k GitHub stars
- Written in Python
Frequently asked questions
Is Arize Phoenix or Prompt flow better?
Neither is universally better. Arize Phoenix has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are Arize Phoenix and Prompt flow free and open-source?
Yes. Arize Phoenix is licensed under Elastic-2.0 and Prompt flow under MIT. Both can be self-hosted at no software cost.
Can I run Arize Phoenix and Prompt flow with Docker?
Arize Phoenix: yes. Prompt flow: yes.
Which is lighter on resources, Arize Phoenix or Prompt flow?
Arize Phoenix has the smaller minimum footprint at 1,024 MB of RAM, compared to about 2,048 MB for Prompt flow. Real-world usage depends on library size, user count, and enabled features.