Postman - The Collaboration Platform for API Development
Google Cloud Endpoints - Google Cloud Endpoints provides the tools to develop, deploy, protect and monitor your APIs.
DreamFactory - DreamFactory is an API management platform used to generate, secure, document, and extend APIs.
Django REST framework - Django REST framework is a toolkit for building web APIs.
AWS CloudTrail - AWS CloudTrail is a web service that records AWS API calls for your account and delivers log files to you.
WSO2 API Manager - WSO2 API Manager is a 100% open source enterprise-class solution that supports API publishing, lifecycle management, application development, access control, rate limiting and analytics in one cleanly integrated system.