ReqRes - A hosted REST-API ready to respond to your AJAX requests.

Insomnia REST - Design, debug, test, and mock APIs locally, on Git, or cloud. Build better APIs collaboratively for the most popular protocols with a dev‑friendly UI, built-in automation, and an extensible plugin ecosystem.

Appbase.io - Search stack for building modern apps

Thunder Client - Rest API client for VS Code, lightweight Postman alternative

Amplication - Instantly generate Node.js apps with GraphQL and REST API

Buddy - The simplest CI/CD tool ever made, acclaimed by top developers worldwide. It uses delivery pipelines to build, test and deploy software. Pipelines are created with over 100 ready-to-use actions, that can be arranged in any way.