The client had a script to validate emails, it wasn't working. I managed to scale the validation process significantly (from 1 email/minute to ~1k emails/minute).
I used FastAPI to create endpoints from a Google Colab Notebook.
I used Gitlab as a version control system.
I created a UI with PyGTK to enable the user to see how much emails are already processed, for how much time the Notebook is running and a log for each validation.
I used threading and asyncio to make the process more efficient. Which lead to the extreme performance boost.