Using python, you can automatically (with cron or heroku scheduler) backup all your Firebase data and store it safely on Google Drive
The result is a new .json file in your S3 bucket whenever you run this script.
virtualenv -p python2.7 --distribute venv
source venv/bin/activate
pip install -r requirements.txt
Set your variables in config.py (copy from config-example.py), generate a Google Credential file and run:
python backup-firebase.py