Update README.md

Author: edoardottt

README.md

@@ -202,6 +202,7 @@ A curated list of awesome search engines useful during Penetration testing, Vuln
 - [SearchFTPs](https://www.searchftps.net/) - The most advanced FTP Search Engine service maintained by members
 - [Ecosyste.ms](https://ecosyste.ms/) - An open API service providing package, version and dependency metadata of many open source software ecosystems and registries
 - [SwaggerHub](https://app.swaggerhub.com/search) - Search public APIs and Domains in SwaggerHub
+- [RapidAPI Public Hub](https://rapidapi.com/hub) - Explore the world's largest API marketplace
 
 ### Email Addresses