doctl (pronounced “dock-tul”, and short for “DigitalOcean Control”) is the official command-line interface for the DigitalOcean API. You can install it using popular package managers like brew and snap.

doctl is one of the simplest paths to automating your DigitalOcean interactions by making them available to shell scripts.

The commands that allow you to automate App Platform interactions live under the doctl apps command space. To create or update your apps, you need to provide a path to the app spec for your app.

Reference for the format of app configuration files for App Platform, also known as “app specs.”
Reference for the DigitalOcean Command-Line Interface (doctl) with App Platform