Adding Holiday API

README.md

@@ -24,6 +24,7 @@ A collective list of JSON APIs for use in web development.
 | Church Calendar API | Catholic liturgical calendar | No | [Go!](http://calapi.inadiutorium.cz/) |
 | Non-working days API | Database of ICS files for non working days | No | [Go!](https://github.com/gadael/icsdb) |
 | Date and Time | Global Date and Time | No | [Go!](http://www.timeanddate.com/services/api/) |
+| Holidays | Free API for obtaining information about holidays. | No | [Go!](http://holidayapi.com/) |
 
 ### Development