head to head · open source
Arize Phoenix vs OpenLIT
Arize Phoenix has 12,128 GitHub stars, 1,261 forks, 970 open issues and last shipped yesterday. OpenLIT has 2,902 stars, 456 forks, 60 open issues and last shipped 2 days ago. Arize Phoenix leads on adoption by 318% (12,128 vs 2,902 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 16%. Arize Phoenix 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 | ★ 2.9K |
| License | Custom / other | Apache-2.0 |
| Written in | Python | TypeScript |
| Last push | 2026-11-04 | 2026-11-03 |
| Forks | ⑂ 1.3K | ⑂ 456 |
| 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
English · 简体中文 Arize Phoenix is Arize's open source AI observability platform designed for experimentation, evaluation, and troubleshooting. For managed production workflows, Arize also offers Arize AX. Phoenix provides: Tracing Trace your LLM application's runtime using OpenTelemetry based instrumentation. Evaluation Leverage LLMs to benchmark your application's performance using response and retrieval evals. Datasets Create versioned datasets of examples for experimentation, evaluation, and fine tuning. Experiments Track and evaluate changes to prompts, LLMs, and retrieval. Playground Optimize prompts, compare…
read the full Arize Phoenix overview →
About OpenLIT
Open source observability & evaluation for AI agents Trace, evaluate, debug, and optimize AI applications and coding agents with OpenTelemetry. ⭐ Star 🚀 Quickstart 📚 Docs Documentation · Quickstart · Examples · Join Slack See what your AI agents are actually doing AI applications are no longer just LLM calls. A production agent can involve: OpenLIT gives you visibility across the entire workflow. Trace every LLM call, tool invocation, prompt, agent step, token, cost, error, and evaluation — using OpenTelemetry. ⚡ Get started in 5 minutes 1. Start OpenLIT Open: 2. Install the SDK Python: TypeScript: 3…
read the full OpenLIT overview →
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Frequently asked questions
Is Arize Phoenix or OpenLIT more popular?
Arize Phoenix has 12,128 GitHub stars and OpenLIT has 2,902. 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 (12,128 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.