Galen Framework - Automated testing of look and feel for your responsive app
Beeceptor - Unblock yourself from API dependencies, and build & integrate with APIs fast. Beeceptor helps you build a mock Rest API in a few seconds.
Reapp - An easier, faster way to build apps with React and JavaScript.
Webhook.site - Instantly generate a free, unique URL and email address to test, inspect, and automate (with a visual workflow editor and scripts) incoming HTTP requests and emails.
RestControl - Modern and powerful framework for testing and validation REST api
MockServer - Easy mocking of any system you integrate with via HTTP or HTTPS.