Outlines

🗒️ Structured outputs for LLMs 🗒️

Made with ❤👷️ by the team at .txt Trusted by NVIDIA, Cohere, HuggingFace, vLLM, etc.

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🚀 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 your schema: share one schema, we show you what breaks under generation, the constraints that fix it, and compliance rates before and after. Sign up here.

Table of Contents

• Why Outlines?
• Quickstart
• Real-World Examples
• 🙋‍♂️ Customer Support Triage
• 📦 E-commerce Product Categorization
• 📊 Parse Event Details with Incomplete Data
• 🗂️ Categorize Documents into Predefined Types
• 📅 Schedule a Meeting with Function Calling
• 📝 Dynamically Generate Prompts with Re-usable Templates
• They Use Outlines
• Model Integrations
• Core Features
• Other Features
• About .txt
• Community

Why Outlines?

LLMs are powerful but their outputs are unpredictable. Most solutions attempt to fix bad outputs after generation using parsing, regex, or fragile code that breaks easily.

Outlines guarantees structured outputs during generation — directly from any LLM.

• Works with any model - Same code runs across OpenAI, Ollama, vLLM, and more
• Simple integration - Just pass your desired output type: model(prompt, output_type)
• Guaranteed valid structure - No more parsing headaches or broken JSON
• Provider independence - Switch models without changing code

The Outlines Philosophy

Outlines follows a simple pattern that mirrors Python's own type system. Simply specify the desired output type, and Outlines will ensure your data matches that structure exactly:

• For a yes/no response, use Literal["Yes", "No"]
• For numerical values, use int
• For complex objects, define a structure with a Pydantic model

Quickstart

Getting started with outlines is simple:

1. Install outlines

pip install outlines

2. Connect to your preferred model

import outlines
from transformers import AutoTokenizer, AutoModelForCausalLM