A boilerplate for one option to test Javascript blob web apps. It uses headless Chrome inside Selenium Docker images to run a simple integration test in Python. If you attach sentry.io to the logger, when the web app is down it sends you angry emails until you fix things.
The idea is you would use this as boilerplate, and then put your tests inside integration/base.py after generating them with something like Katalon Recorder (Firefox extension, Chrome extension) and editing by hand.
Selenium can be a bit tricky to get working correctly, so this version- locked Docker image hopefully gives you a head start. And you can run it anywhere you choose rather than being locked in to a proprietary service.
To run, use docker-compose:
docker-compose build
docker-compose up