What are some alternatives?
When comparing Apigee and Gravitee.io, you can also consider the following products
Postman Collections - Biggest library of ready-made API collections for Postman
Tyk - Tyk is an open-source API gateway and API management platform.
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.
Paw - Paw is a REST client for Mac.
Apiary - Collaborative design, instant API mock, generated documentation, integrated code samples, debugging and automated testing
Amazon API Gateway - Create, publish, maintain, monitor, and secure APIs at any scale