Which python framework will be suitable to rest api only

as of SEP18, also have a look on Quart, APIstar
as of MAR19, add fastAPI, looks very promising

nota: Bottle is lighter (& faster) than Flask, but with less bells & whistles
Falcon is fast ! fastAPI is fast as well !

also, as Bottle/Flask are more general frameworks (they have templating features for instance, not API related), frameworks such as Falcon or fastAPI are really designed to serve as APIs framework.

Lightweight python frameworks

  1. Flask - http://flask.pocoo.org/
  2. Falcon -https://falconframework.org/
  3. Bottle - https://bottlepy.org/docs/dev/

If using Flask you can use Flask-RESTPlus which has inbuild SwaggerUi - https://flask-restplus.readthedocs.io/en/stable/