Amazon API Gateway - Create, publish, maintain, monitor, and secure APIs at any scale
Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
Postman - The Collaboration Platform for API Development
Dokku - Docker powered mini-Heroku in around 100 lines of Bash
DreamFactory - DreamFactory is an API management platform used to generate, secure, document, and extend APIs.
Google Cloud Functions - A serverless platform for building event-based microservices.