Where can I find websites or servers for testing of Rest api requests?

Trying to create a mobile application in the study of the Rest api are faced with the problem of testing and processing of queries the rest api. Need server c simple authorization get a token and then switch to Oauth2 authentication.0, to test the queries and their processing. Found the solution with the json server, but knowledge of js could be used only as an example. Tell me any sites or servers with simple authentication, for testing purposes, once you've mastered that you can move to Oauth2.0.