Hoppscotch : A free, online, open source API request builder
Bliss.js : Want to use Vanilla JS but find native APIs a bit unwieldy? Bliss is for you
Val Town : Val Town is a social website to write and run code. Vals are small JavaScript/TypeScript snippets that run on their servers. You can create APIs, sche...
Mockoon : Mockoon is the easiest and quickest way to design and run mock APIs. No remote deployment, no account required, free and open-source.
Postman : Save requests and organize your APIs into Collections. Create and send any HTTP request using the awesome Postman request builder. Write your own test...
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.