A small language for typed model functions, compiled into the client you call. Built by Boundary.
Others in typed output
InstructorStructured output from any model, validated.
Pydantic AIType safe agents, from the Pydantic team.
Guidance
LMQLCommon questions
Is BAML free to use?
BAML is open source and free to run yourself. You still pay whichever model provider you point it at, and this tutorial is free with no signup.
Do I need to know Python to use BAML?
Basic Python is enough. Functions, dictionaries and imports cover most of what BAML asks of you.
When should I not use BAML?
When something else in typed output fits the job better. The others in that group are listed below.
Lessons for BAML are being written. Meanwhile the APIs for AI tutorial covers the same ground: state, tools, loops, memory and human approval. Most of it carries straight over.
Start the APIs for AI tutorial →