Whatever you are developing, you are most likely contacting or creating a web API.
For quickly testing web APIs, there are numerous tools you can use to do requests, instead of before implementing everything in code. This can quickly speed up the development process, and discover bugs and problems with the API early.
For almost two years now, I have been used to using Fiddler for doing HTTP requests and testing APIs.
A few days ago, I came across a Chrome extension called Postman, which is also a great tool to test APIs.
It may not be as feature rich as Fiddler, but It is very handy and easy to use, just install the Chrome extension, and bookmark the website that shows up as a Chrome tab after installation!