Rest is a HTTP construction tool, which is useful to develop, test and debug REST-full APIs and services. You can also use it to make any kind of requests to any HTTP application and it even includes special features such as support for curl commands.
Rest Vs. Resend
You will notice that both Rest and Resend are similar in nature. This is because Rest was designed after Resend but it lacks the passive vulnerability detection engine. However, Rest comes handy in many situations and is perfect for manually inspecting REST-full services.