Using netcat to Mock a RESTful Webservice that Returns JSON

Let’s say that you are working on a part of a project that needs to consume some JSON data from a forthcoming HTTP service.  That sub-system is being developed by one of your colleagues and is not yet ready for you to stand-up to develop against.

You can use netcat to mock the webservice and return some static JSON data for which you can develop and test against with a simple one-liner.

First, put together your JSON in a file, ‘my.json’ and then run the following command in a terminal:

while true; do echo -e "HTTP/1.1 200 OK\r\n\r\n$(cat my.json)" | nc -l 9998; done

An hitting http://localhost:9998 will return your test JSON data.