Postman is a powerful GUI platform to make your API development faster & easier, from building API requests through testing, documentation and sharing.
Postman was designed from the ground up, to support all aspects of API development. Postman's apps are built on a single underlying layer, ensuring consistent performance and user experience. Postman has Run, Test, Document & Monitor features, designed to work seamlessly together. Postman was designed to make your current workflow faster and better.
Postman has options for the developer in everyone:
Both 3scale and Apiary are great tools for managing APIs. 3scale has some great features to offer such as log tracking, single sign-on, custom branding, analytics etc. 3scale has two plans - a Pro plan that is priced at $750 perAPI Management Services