LMQL

A programming language for LLM interaction, built as a superset of Python

About LMQL

LMQL is an open-source query language for large language models, developed by the SRI Lab at ETH Zurich. It lets developers interleave Python control flow with prompts, typed variables and hard constraints on generated output, and runs portably across backends including OpenAI, Azure OpenAI and Hugging Face Transformers. It ships with a playground IDE and VS Code tooling. It is for developers who need precise, programmatic control over model behavior.

LMQL website preview

Live preview of lmql.ai via the WordPress mShots service — it can take a few seconds to generate on a first visit.

LMQL: strengths & things to check

Strengths

Completely free to use — this directory lists no paid plan for it.
Covers open source, prompting, python, llm — see the focus areas listed in its key facts.
Has 6 close alternatives in the same category on this page, so switching or comparing is easy.

Things to check

Free tools can change their model or shut down — avoid locking critical work into it without an export path.
Current plan prices are not listed here (they change too often to print reliably) — confirm the exact price on the official site.
It is one of 1164 tools in the Developer Tools category here — compare it against the alternatives below before you commit.

Derived from this listing's own data (pricing model, focus areas and category) — not a hands-on review score.

LMQL pricing

Pricing model	Free — listed in this directory as a free tool, with no paid plan required to use it.
Free access	Yes — fully free
Current plan prices	Listed on the official site — prices change, so this directory links out instead of printing a number that may already be stale.
Official site	lmql.ai

LMQL key facts

Category: Developer Tools
Pricing: Free — listed in this directory as a free tool, with no paid plan required to use it.
Focus areas: open source, prompting, python, llm
Official site: lmql.ai

LMQL FAQ

How much does LMQL cost?

Free — listed in this directory as a free tool, with no paid plan required to use it. Current plans and prices are listed on the official site (lmql.ai).

What is LMQL used for?

A programming language for LLM interaction, built as a superset of Python Its focus areas in the Developer Tools category: open source, prompting, python, llm.

Where can I try LMQL?

On its official site, lmql.ai — the Visit Official Site button above goes straight there.

LMQL vs alternatives

	LMQL	Instructor	Chainlit	git-cola
Pricing	Free — listed in this directory as a free tool, with no paid plan required to use it.	Free — listed in this directory as a free tool, with no paid plan required to use it.	Free — listed in this directory as a free tool, with no paid plan required to use it.	Free — listed in this directory as a free tool, with no paid plan required to use it.
Focus areas	open source, prompting, python, llm	llm, structured output, pydantic, python, open source	open source, python, conversational ai, framework, chat ui	git, gui, open source, python
Official site	lmql.ai	python.useinstructor.com	chainlit.io	git-cola.github.io
Directory status	Listed	Listed	Listed	Listed

Side-by-side from each listing's own directory data. Full alternative cards are below.

About the Developer Tools category

Editors, platforms, and services developers rely on to build and ship software. The Developer Tools category on Tools Hub currently lists 1164 tools. Alongside LMQL, it includes ChatWithCloud, Pagerly, StarOps, GoCodeo.

FreeDeveloper Toolsopen-sourcepromptingpythonllm

Alternatives to LMQL

Tools in the same Developer Tools category that share focus areas with LMQL — worth comparing before you commit:

Developer Tools

Instructor

Extract structured data from any LLM with type safety and validation

Freellmstructured-outputpydanticpython

Developer Tools

Chainlit

Open-source Python framework for building production-ready conversational AI applications.

Freeopen-sourcepythonconversational-aiframework

Developer Tools

git-cola

Sleek and powerful Git GUI written in Python

Freegitguiopen-sourcepython

Developer Tools

GoModel

Open-Source AI Gateway with Workflows, Aliases, and Usage Tracking

Freeai-gatewayllmopen-sourceself-hosted

Developer Tools

Kiln AI

Build, evaluate, and optimize AI systems with evals and fine-tuning.

Freemiumllmevalsfine-tuningopen-source

Developer Tools

Locust

Load testing framework written in Python

Freeload-testingpythonopen-source

More in Developer Tools

Comparing tools in the Developer Tools category? These related listings are worth a look: ChatWithCloud — AWS natural language CLI: ask your AWS account questions in your terminal; Pagerly — On-calls, rotations, incidents and tasks on Slack and Microsoft Teams; StarOps — AI platform engineer by Ingenimax for deploying and troubleshooting cloud infrastructure.