My team built a new JS framework for mocking REST APIs called "unmock" that focuses on fuzz testing integrations. We hope to move it closer to property-based testing libraries like fast-check. The hard part is building a shrinker - shrinkers (<a href="https://medium.com/criteo-labs/introduction-to-property-based-testing-f5236229d237" rel="nofollow">https://medium.com/criteo-labs/introduction-to-property-base...</a>) are tough to get right when testing side effects. Please check out the article, leave your feedback if any, try out unmock (<a href="https://github.com/Meeshkan/unmock-js" rel="nofollow">https://github.com/Meeshkan/unmock-js</a>) and let me know what you think!