What is Postman?

Postman is an API platform for building and using APIs. Postman simplifies each step of the API lifecycle and streamlines collaboration so you can create better APIs—faster.

New updates :

Store and reuse scripts everywhere with the package library
Available on Free, Basic, Professional, and Enterprise plans

With the new Package Library, teams can now store and reuse test scripts for more efficient and reliable API testing. Test script packages can contain business logic and code, which can be consumed in multiple requests by just referencing the package in various places within the team. Change once, use everywhere. No more copy-pasting. No more redundant code.
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Package Library: **

Configure request and collection runs using the Postman Runtime library. The library is an open-source Node.js project you can use for low-level configuration over request sending in your API development and testing projects.

runtime = require('postman-runtime');
var runner = new runtime.Runner();

var collection = new sdk.Collection();

runner.run(collection, {
  data: [],
  timeout: {
    request: 30000,
    script: 5000
  },
  iterationCount: 1,

  //other options...

},
function (err, run) {
  //Callbacks to execute as the collection runs
  run.start(callbacks);
});

You can use the Runtime library if you need a detailed configuration of your request runs, for example as part of an automation workflow to integrate Postman Collection runs into your development pipeline.