head to head · open source
Mem0 vs outlines
Mem0 has 68,288 GitHub stars, 8,104 forks, 742 open issues and last shipped 4 days ago. outlines has 15,998 stars, 911 forks, 166 open issues and last shipped 1 months ago. Mem0 leads on adoption by 327% (68,288 vs 15,998 stars). Mem0 is written in Python under Apache-2.0; outlines is written in Python under Apache-2.0. Mem0 has attracted 12% as many forks as stars, outlines 6%. Mem0 was the more recently maintained of the two, and both are self-hostable with no licence fee.
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
| Mem0 | outlines | |
|---|---|---|
| GitHub stars | ★ 68K | ★ 16K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Python | Python |
| Last push | 2026-10-30 | 2026-09-21 |
| Forks | ⑂ 8.1K | ⑂ 911 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Mem0 if
- You weight community size — 68K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick outlines if
- You want the outlines feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and outlines fits your workflow better
About Mem0
Learn more · Join Discord · Demo 📄 Benchmarking Mem0's token efficient memory algorithm → New Memory Algorithm (April 2026) All benchmarks run on the same production representative model stack. Single pass retrieval (one call, no agentic loops) at a top 200 retrieval budget. Scores reflect Mem0's managed platform, which includes proprietary optimizations not available in the open source SDK; open source users should expect directionally similar gains but not identical numbers. What changed: Single pass ADD only extraction one LLM call, no UPDATE/DELETE. Memories accumulate; nothing is overwritten. Agent…
About outlines
🗒️ Structured outputs for LLMs 🗒️ Made with ❤👷️ by the team at .txt Trusted by NVIDIA, Cohere, HuggingFace, vLLM, etc. [![PyPI Version][pypi version badge]][pypi] [![Downloads][downloads badge]][pypistats] [![Stars][stars badge]][stars] [![Discord][discord badge]][discord] [![Blog][dottxt blog badge]][dottxt blog] [![Twitter][twitter badge]][twitter] The .txt API is currently in early access. Request access here → 🚀 Building the future of structured generation We're working with select partners to develop new interfaces to structured generation. Need XML, FHIR, custom schemas or grammars? Let's talk. Audit…
read the full outlines overview →
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Frequently asked questions
Is Mem0 or outlines more popular?
Mem0 has 68,288 GitHub stars and outlines has 15,998. Mem0 has the larger community by that measure.
Are Mem0 and outlines free?
Both are open source. Mem0 is licensed under Apache-2.0 and outlines under Apache-2.0. Neither carries a licence fee.
What is the difference between Mem0 and outlines?
Mem0 is written in Python and outlines 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, Mem0 or outlines?
Choose Mem0 if you want the larger community (68,288 stars) or its Apache-2.0 licence terms. Choose outlines if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.