OpenAPI definitions and code generation for Lean

Input: OpenAPI spec
Output: Lean bindings for each endpoint

The generated bindings are functions that construct HTTP requests as defined by the http package. These requests can then be sent over the wire with e.g. Socket.lean.


Add the following to your lakefile.lean:

require Ā«lean-openapiĀ» from git "" @ "main"

Then, in a file:

import LeanOpenAPI

-- The declarations are generated in the namespace where the macro is invoked
namespace MyLib
-- The `genOpenAPI!` macro is scoped, so we need to open this namespace:
open LeanOpenAPI.Meta
-- now we can generate the API. the argument must have type `IO String`
-- and should be the json string for the OpenAPI spec
genOpenAPI! (IO.FS.readFile "examples/")


A list of features of OpenAPI not (yet!) supported. PRs welcome :-)

  • Some restrictions on parameter objects are not enforced.
  • Parameter object's allowEmptyValue field is always ignored.
  • Meta-schemas are mostly unsupported; the current behavior puts the meta-schema in the docstring, and provides an over-approximation of the argument type, expecting users to adhere to the docstring's meta-schema.
  • Security requirements are not supported
  • Examples are recognized but unused