Review on FakeJSON by Justin Early

Easy integration, great support from their team (especially with NodeJS), easy setup of tests using Mocha/Chai/Sinon (I'm sure there's more but I don't know them).

The documentation could be improved a bit - some examples would help especially if you are new to JS testing. Also it might be helpful to have an example that shows how to use several different methods (expect vs chai-http vs sinon) together. We needed something fast, reliable & free solution to generate random strings, numbers etc at runtime during our automated regression tests.