Flasgger
Easy OpenAPI specs and Swagger UI for your Flask API
...Flasgger can work with simple function views or MethodViews using docstring as specification, or using @swag_from decorator to get specification from YAML or dict and also provides SwaggerView which can use Marshmallow Schemas as specification. Flasgger is compatible with Flask-RESTful so you can use Resources and swag specifications together, take a look at the restful example. Flasgger also supports Marshmallow APISpec as base template for specification.