Create script + API to enrich JSON with emails using 3rd-party API

I need an expert in setting up scripts + an API that enriches data with emails using a 3rd-party API, then creates a CSV with the results.

We have our app set up on the front-end already, but now need some help on the back-end side. Here's the general workflow:

- API you've built receives parsed CSV file (JSON)
- Identify relevant columns ("email" "name" "domain")
- Run through 3rd-party API (anymailfinder.com most likely, or similar)
- Store results
- Run through 2nd 3rd-party API (millionverifier.com)
- Process & count the results
- Create a CSV with the results
- Post results to endpoint we provide you with

Please provide me with relevant examples of previous jobs completed.