API.AI : With API.AI, you can create conversational scenarios within minutes, then build advanced dialogues to manage the conversation flow with the user. Once...
Mockbin : Mockbin allows you to generate custom endpoints to test, mock, and track HTTP requests & responses between libraries, sockets and APIs.
AI21 Studio : AI21 Studio allows users to generate text completions for an input prompt using Jurassic-1 language models.
Strapi : Open source Node.js Headless CMS to easily build customisable APIs
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.