Hi!
I've worked extensively with numerous APIs in PHP and Javascript, from Wordpress to NodeJS, Facebook and I've built my own custom APIs for clients. This wouldn't be significantly harder or more complex to implement.
In addition I've actually worked on an open-source project that takes data from an API and converts it into a downloadable excel sheet. The script will automatically generate an Excel sheet right in your browser, so you wouldn't even need to worry about storing and updating the information.
To summarize:
1. I have worked with and built APIs. I understand them well.
2. I have worked on dynamically generating Excel sheets from API data.
3. I work in PHP and Javascript, which are what you need to get this job done.