What are some alternatives?
When comparing Restlet and Sauce Labs, you can also consider the following products
Postman Collections - Biggest library of ready-made API collections for Postman
TestComplete - TestComplete Desktop, Web, and Mobile helps you create repeatable and accurate automated tests across multiple devices, platforms, and environments easily and quickly.
Paw - Paw is a REST client for Mac.
soapUI - SoapUI Pro is one of the most prominent API testing platforms around, allowing developers to quickly prototype the functions of their apps and get them to market with little hassle.
Amazon API Gateway - Create, publish, maintain, monitor, and secure APIs at any scale
BrowserStack - Test your website for cross browser compatibility on real browsers. Instant access to multiple desktop and mobile browsers. Get Free Trial.