head to head · open source
PageIndex vs Arize Phoenix
PageIndex has 39,973 GitHub stars, 3,442 forks, 103 open issues and last shipped 2 days ago. Arize Phoenix has 12,128 stars, 1,261 forks, 970 open issues and last shipped yesterday. PageIndex leads on adoption by 230% (39,973 vs 12,128 stars). PageIndex is written in Python under MIT; Arize Phoenix is written in Python under a custom or non-standard licence. PageIndex has attracted 9% as many forks as stars, Arize Phoenix 10%. 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 (agents), 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
| PageIndex | Arize Phoenix | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 12K |
| License | MIT | Custom / other |
| Written in | Python | Python |
| Last push | 2026-11-03 | 2026-11-04 |
| Forks | ⑂ 3.4K | ⑂ 1.3K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick PageIndex if
- You weight community size — 40K stars and counting
- You want the MIT license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick Arize Phoenix if
- You want the Arize Phoenix feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches Python
- You evaluated both and Arize Phoenix fits your workflow better
About PageIndex
PageIndex: Vectorless, Reasoning based RAG Reasoning based RAG ◦ No Vector DB, No Chunking ◦ Context Aware Retrieval ◦ Reads Like a Human 🌐 Website • ☁️ Cloud • 📖 Docs • 📝 Blog • ✉️ Contact Updates [Aug '26] 🔥 PageIndex SDK : pip install U pageindex now ships local mode : index, retrieve, and chat entirely on your machine with your own LLM key, or point the same client at PageIndex Cloud with an API key. [Aug '26] ⚡ PageIndex Flash : fast tree index generation for text based PDFs, now the default indexing method in PageIndex SDK local mode. Scale PageIndex to Millions of Documents: PageIndex File System is a…
read the full PageIndex overview →
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 →
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Frequently asked questions
Is PageIndex or Arize Phoenix more popular?
PageIndex has 39,973 GitHub stars and Arize Phoenix has 12,128. PageIndex has the larger community by that measure.
Are PageIndex and Arize Phoenix free?
Both are open source. PageIndex is licensed under MIT, and Arize Phoenix has no licence declared in this registry. Both are free to self-host.
What is the difference between PageIndex and Arize Phoenix?
PageIndex is written in Python and Arize Phoenix in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, PageIndex or Arize Phoenix?
Choose PageIndex if you want the larger community (39,973 stars) or its MIT licence terms. Choose Arize Phoenix if its feature set, stack or Custom / other licence fits better. Both are self-hostable.