Business requirements The app should use Pay On API to handle a basic payment transaction to the test bank account. Everything you need can be found in the docs. Also you can take a look at the examples All data should be validated. Do not allow to donate more than 100 eur or usd. Prevent form from submitting multiple times Store information about transaction in localstorage (amount, currency, buildNumber, timestamp, ndc, id) Same user can donate only 1 time in hour (if user already donated recently, show him a thanks page with donation info, else show form) Technical requirements It should be a single page application (SPA). In the end you should have one index.html file that includes one .js file and one .css file You need to develop the whole app that it could be placed in to AWS S3 bucket and served as a static website. (Ideally you could upload it to your own S3 bucket if you have one or use github pages) You can use any front-end framework you like (preferably Angular or React) Use ES2015 syntax (transpile it with babel) Use some css preprocessor like scss or stylus All logic should be developed using ajax calls to api and localstorage for storing temp data. No database is required.