head to head · open source
Arize Phoenix vs OpenLIT
Arize Phoenix has 11,544 GitHub stars, 1,140 forks, 970 open issues and last shipped yesterday. OpenLIT has 2,772 stars, 394 forks, 60 open issues and last shipped yesterday. Arize Phoenix leads on adoption by 316% (11,544 vs 2,772 stars). Arize Phoenix is written in Python under a custom or non-standard licence; OpenLIT is written in TypeScript under Apache-2.0. Arize Phoenix has attracted 10% as many forks as stars, OpenLIT 14%. OpenLIT was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (ai-observability), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Arize Phoenix | OpenLIT | |
|---|---|---|
| GitHub stars | ★ 12K | ★ 2.8K |
| License | Custom / other | Apache-2.0 |
| Written in | Python | TypeScript |
| Last push | 2026-09-19 | 2026-09-19 |
| Forks | ⑂ 1.1K | ⑂ 394 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Arize Phoenix if
- You weight community size — 12K stars and counting
- You want the Custom / other license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick OpenLIT if
- You want the OpenLIT feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches TypeScript
- You evaluated both and OpenLIT fits your workflow better
About Arize Phoenix
Arize Phoenix is an open source AI observability platform for experimentation, evaluation, and troubleshooting. It lives in the machine learning infrastructure ecosystem and is written in Python. The project provides tracing, evaluation, datasets, experiments, prompt management, and a playground for LLM applications.
read the full Arize Phoenix overview →
About OpenLIT
OpenLIT is an open source, OpenTelemetry native observability and evaluation platform for AI applications, AI agents and coding agents, built for engineers who run LLM backed systems and need to see what those systems actually did.
read the full OpenLIT overview →
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Frequently asked questions
Is Arize Phoenix or OpenLIT more popular?
Arize Phoenix has 11,544 GitHub stars and OpenLIT has 2,772. Arize Phoenix has the larger community by that measure.
Are Arize Phoenix and OpenLIT free?
Both are open source. Arize Phoenix has no licence declared in this registry, and OpenLIT is licensed under Apache-2.0. Both are free to self-host.
What is the difference between Arize Phoenix and OpenLIT ?
Arize Phoenix is written in Python and OpenLIT in TypeScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Arize Phoenix or OpenLIT ?
Choose Arize Phoenix if you want the larger community (11,544 stars) or its Custom / other licence terms. Choose OpenLIT if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.