The OASIS Fountain OAPP built on top of the WEB4 OASIS API using the WEB4 OASIS API JS/NPM Package:
https://github.com/NextGenSoftwareUK/OASIS-API-Javascipt-Package
It also uses the WEB4 OASIS API React Component Library here:
https://github.com/NextGenSoftwareUK/OASIS-React-UI-Component-Library