Arize Phoenix vs OpenLLMetry
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 | OpenLLMetry |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 93 · Excellent | 91 · Excellent |
| Category | Self-Hosted AI | Self-Hosted AI |
| License | Elastic-2.0 | Apache-2.0 |
| Language | Python | Python |
| Setup difficulty | Medium | Medium |
| Min. RAM | 1,024 MB | 512 MB |
| Deployment | docker, source | docker, source |
| GitHub stars | ★ 11,594 | ★ 7,445 |
| First released | 2023 | 2023 |
| Replaces | LangSmith, Helicone | LangSmith, Datadog LLM Observability |
What are Arize Phoenix and OpenLLMetry?
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
OpenLLMetry
OpenLLMetry is a set of OpenTelemetry extensions from Traceloop that add observability to LLM applications. It instruments calls to model providers and vector databases so traces and metrics can be sent to any self-hosted backend.
- OpenTelemetry-based tracing
- Instruments popular LLM SDKs
- Vendor-neutral export
- Vector database instrumentation
Arize Phoenix vs OpenLLMetry: key differences
Both projects are written in Python. Licensing differs — Elastic-2.0 for Arize Phoenix versus Apache-2.0 for OpenLLMetry. OpenLLMetry is the lighter option, starting around 512 MB of RAM against 1,024 MB for Arize Phoenix.
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 OpenLLMetry if…
- Released under the Apache-2.0 license
- First-class Docker support for quick deployment
- Mature project with 7.4k GitHub stars
- Written in Python
Frequently asked questions
Is Arize Phoenix or OpenLLMetry 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 OpenLLMetry free and open-source?
Yes. Arize Phoenix is licensed under Elastic-2.0 and OpenLLMetry under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Arize Phoenix and OpenLLMetry with Docker?
Arize Phoenix: yes. OpenLLMetry: yes.
Which is lighter on resources, Arize Phoenix or OpenLLMetry?
OpenLLMetry has the smaller minimum footprint at 512 MB of RAM, compared to about 1,024 MB for Arize Phoenix. Real-world usage depends on library size, user count, and enabled features.