Add npm registry (#2464)

README.md

@@ -464,6 +464,7 @@ API | Description | Auth | HTTPS | CORS |
 | [MicroENV](https://microenv.com/) | Fake Rest API for developers | No | Yes | Unknown |
 | [Mocky](https://designer.mocky.io/) | Mock user defined test JSON for REST API endpoints | No | Yes | Yes |
 | [Nationalize.io](https://nationalize.io) | Estimate the nationality of a first name | No | Yes | Yes |
+| [npm Registry](https://github.com/npm/registry/blob/master/docs/REGISTRY-API.md) | Query information about your favorite Node.js libraries programatically | No | Yes | Unknown |
 | [OneSignal](https://documentation.onesignal.com/docs/onesignal-api) | Self-serve customer engagement solution for Push Notifications, Email, SMS & In-App | `apiKey` | Yes | Unknown |
 | [OOPSpam](https://oopspam.com/) | Multiple spam filtering service | No | Yes | Yes |
 | [Open Page Rank](https://www.domcop.com/openpagerank/) | API for calculating and comparing metrics of different websites using Page Rank algorithm | `apiKey` | Yes | Unknown |