Overview
LMQL (Language Model Query Language) is a programming language designed specifically for working with large language models. Developed at ETH Zurich, LMQL combines SQL-like syntax with Python to provide declarative constraints on LLM outputs. It allows developers to specify what they want from an LLM using familiar query patterns rather than imperative code.
The language supports constraints, control flow, and scripting capabilities, making it possible to express complex LLM interactions concisely. LMQL's runtime optimizes queries to minimize token usage while ensuring constraints are satisfied, making it both expressive and efficient.
Key Features
**SQL-Like Syntax**: Familiar query language for LLMs**Declarative Constraints**: Specify what you want, not how to get it**Type Constraints**: Ensure outputs match types and patterns**Control Flow**: Conditionals and loops in query language**Python Integration**: Embed Python expressions seamlessly**Multi-Model Support**: Works with various LLM backends**Optimized Execution**: Minimizes token usage automatically**Playground**: Interactive web-based development environmentWhen to Use LMQL
LMQL is ideal for:
Research projects exploring LLM capabilitiesApplications with complex output constraintsTeams preferring declarative programmingProjects requiring token-efficient generationDevelopers familiar with SQLRapid prototyping of LLM interactionsPros
Novel declarative approach to LLM programmingConcise expression of complex constraintsAutomatic optimization of token usageStrong research foundation from ETHInteractive playground for developmentWorks across multiple modelsType safety for outputsGood for exploratory developmentCons
New language with learning curveSmaller community and ecosystemStill in research/beta stageLess production adoptionLimited compared to full frameworksDocumentation still evolvingMay not integrate with existing codebases easilyTooling and IDE support limitedPricing
**Open Source**: Free, Apache 2.0 license**Self-Hosted**: Free to use anywhere**No Commercial Offering**: Pure research project