openapi: 3.0.0
info:
  title: API to upload a file
  version: 1.0.0
paths:
  /files/{filename}:
    put:
      parameters:
        filename:
          in: path
          schema:
            type: string
      requestBody:
        content:
          application/octet-stream:
            schema:
              type: string
              format: binary