Request inspector - Debug web hooks, http clients
Beeceptor - Unblock yourself from API dependencies, and build & integrate with APIs fast. Beeceptor helps you build a mock Rest API in a few seconds.
MockServer - Easy mocking of any system you integrate with via HTTP or HTTPS.
CurlHub.io - API Traffic Inspector
SOAP/REST Mock Service - Download SOAP/REST Mock Service for free.
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.