Any requests you send to /capture/[tag]/... will be stored and can then be viewed. This is useful for API's that accept a callback URL and send back their response asynchronously.
See the Getting Started page for more details: http://requestcapture.appspot.com/start
Requires Java and Maven to build + run locally (tested most recently with Java 1.7 and Maven 3.2.2)
To build it:
mvn clean install
To start/stop it:
mvn appengine:devserver_start
mvn appengine:devserver_stop
To deploy the latest:
mvn appengine:update
See https://cloud.google.com/appengine/docs/java/tools/maven for more details.