# Outlines

> Apache-2.0 structured generation: JSON Schema, regex or grammar

**Category:** AI Agents  
**Pricing:** open-source  
**URL:** https://dottxt-ai.github.io/outlines/  
**GitHub:** https://github.com/dottxt-ai/outlines  
**Added:** 2026-10-20

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## The Hook

Outlines is a Python library for structured generation: it constrains LLM output to a JSON Schema, a regex or a grammar, so you get valid structure instead of hoping the prompt works.

## What's Good

Apache-2.0 (dottxt-ai/outlines), release 1.3.3 (2026-08-06). Useful when downstream code needs output that always parses.

## The Catch

Last commit 2026-08-24. The strongest guarantees come with local or self-hosted models, not with every API. ★~16k in about 187 weeks (~85 a week) with 60 watchers: judge it on the library, not the star count.

## Verdict

The standard library for constrained output, best with models you run yourself.