History.js : History.js gracefully supports the HTML5 History/State APIs (pushState, replaceState, onPopState) in all browsers. Including continued support for dat...
Hoppscotch : A free, online, open source API request builder
Anything to Triples : Anything To Triples (any23) is a library, a web service and a command line tool that extracts structured data in RDF format from a variety of Web docu...
pump.io : Social server with an ActivityStreams API. It's a stream server that does most of what people really want from a social network.
Data Science Toolkit : A collection of the best open data sets and open-source tools for data science, wrapped in an easy-to-use REST/JSON API with command line, Python and ...
Bluepine is a DSL for defining API Schema/Endpoint with the capabilities to generate Open API (v3) spec, validate API request and serialize object for API response based on single schema definition.