This simple example app uses Dropbox webhooks to convert TextGrid files to CSV
Read more about webhooks and this example on the Dropbox developers site.
You can just set the required environment variables (using .env_sample as a guide) and run the app directly with python app.py.
You can deploy directly to Heroku with the button below. First you'll need to create an API app via the App Console. Make sure your app has access to files (not just datastores), and answer "Yes - My app only needs access to files it creates" to ensure your app gets created with "App folder" permissions.
Once you've deployed, you can easily clone the app and make modifications:
$ heroku clone -a new-app-name
...
$ emacs index.js
$ git add .
$ git commit -m "update index.js"
$ git push heroku master
...