Convert Postman Collection to OpenAPI Yaml

Download this tool:

npm i postman-to-openapi -g

On Postman Click on Export and export the collections as JSON.

Then on CLI run:

p2o ./path/to/PostmantoCollection.json -f ./out_openapi_.yml

This will create the OpenAPI Schema at out_openapi_.yml.

Open this file in a text editor of your choice and update the basePathUrl and any other variables.