head to head · open source
outlines vs E2B
outlines has 15,825 GitHub stars, 880 forks, 166 open issues and last shipped 9 days ago. E2B has 13,855 stars, 1,039 forks, 59 open issues and last shipped yesterday. outlines leads on adoption by 14% (15,825 vs 13,855 stars). outlines is written in Python under Apache-2.0; E2B is written in Python under Apache-2.0. outlines has attracted 6% as many forks as stars, E2B 7%. E2B 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
| outlines | E2B | |
|---|---|---|
| GitHub stars | ★ 16K | ★ 14K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Python | Python |
| Last push | 2026-09-09 | 2026-09-17 |
| Forks | ⑂ 880 | ⑂ 1.0K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick outlines if
- You weight community size — 16K 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 E2B if
- You want the E2B 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 E2B fits your workflow better
About outlines
Outlines is a Python library for structured generation with large language models, released under the Apache 2.0 license and maintained by the team at .txt. It lives in the AI and machine learning ecosystem, specifically among AI development platforms and structured generation tooling, and it is distributed through PyPI. The project describes itself as a way to guarantee structured outputs during generation rather than repairing them afterward, and its topic list places it alongside work on context free grammars, regular expressions, JSON, prompt engineering, and symbolic AI.
read the full outlines overview →
About E2B
E2B is open source infrastructure that runs AI generated code in secure isolated cloud sandboxes. It lives in the AI development platform ecosystem for agents, and it provides JavaScript, TypeScript, and Python SDKs for starting and controlling those sandboxes.
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Frequently asked questions
Is outlines or E2B more popular?
outlines has 15,825 GitHub stars and E2B has 13,855. outlines has the larger community by that measure.
Are outlines and E2B free?
Both are open source. outlines is licensed under Apache-2.0 and E2B under Apache-2.0. Neither carries a licence fee.
What is the difference between outlines and E2B?
outlines is written in Python and E2B 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, outlines or E2B?
Choose outlines if you want the larger community (15,825 stars) or its Apache-2.0 licence terms. Choose E2B if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.