Apps Script
Also called Google Apps Script · App Script
Google's built-in scripting language for automating Sheets, Docs, and other Workspace apps, the layer that wires a spreadsheet to an external API.
In more detail
Apps Script runs JavaScript-like code directly inside a Google Sheet, with permission to read and write cells, call external services, and run on a menu click or a schedule. That combination, a familiar spreadsheet interface with a script layer bolted on, is what turns a plain Sheet into the front end of a small production tool without needing a hosted application or a server.
Example
A Sheet holding a config tab (model, target word count, prompt fields) can call the Claude API from an Apps Script function triggered by a custom menu button, write the returned script into a document, and log the run, all without leaving the spreadsheet.
Why it matters
Because the whole tool lives inside a Sheet you own, there is nothing to migrate if a vendor changes terms or shuts down: the prompts, the logic, and the output are already in files under your own Google account. Most of the actual script can be generated from a plain-English description by an AI coding assistant, which is why the setup cost is closer to a weekend than a software project.