Both tools remove repetitive work: sending reminders, moving files, updating spreadsheets, routing email. They feel similar from a distance, but they are built for different worlds, and picking the wrong one creates friction for years.
The short rule
Automate inside the suite you already use. If your company runs on Gmail, Drive and Sheets, Apps Script can reach all of it with no extra licences. If you run on Outlook, SharePoint and Teams, Power Automate is already wired into those services. Crossing suites is possible, but every connector you add is another thing to secure and maintain.
How they differ
| Google Apps Script | Power Automate | |
|---|---|---|
| How you build | JavaScript code in the browser or locally with clasp | Visual, drag-and-drop flows |
| Best at | Custom logic, web apps, document generation, Sheets/Drive/Gmail | Approvals, notifications, SharePoint and Teams workflows |
| Interfaces | Can serve full web apps with pages and login | Relies on Power Apps, Forms or SharePoint for screens |
| Cost | Included, within quotas | Standard connectors included; premium needs licences |
| Testing | Automated tests are possible with the right setup | Mostly manual testing of each flow |
When Power Automate is the better choice
- You live in Microsoft 365 and need approvals, reminders or file moves between SharePoint, Outlook and Teams.
- The people maintaining the automation are not developers.
- Each flow is short: a trigger, a few steps and a notification.
When Apps Script is the better choice
- You live in Google Workspace.
- You need real business rules, calculations or documents generated from templates.
- You want a proper internal tool: pages, roles, a client portal, not just a background job.
What we learned running both in production
At a US consulting firm we did both: we rebuilt their Microsoft 365 estate with 10 Power Automate flows, then built the processes Microsoft could not handle as a Google Apps Script platform. The lesson: visual flows are excellent for simple routing, but once a process has many rules, a codebase with tests is far easier to change safely. Our platform has 2,203 automated tests, and that is what lets it change weekly without breaking.
Our recommendation
- List the process step by step before choosing a tool.
- Start in the suite you already pay for.
- Use visual flows for simple routing; move to code when the rules pile up.
- Whatever you choose, document it so it does not depend on one person.
Not sure where your process fits? Tell us about it and we will recommend the simplest option, even if it is not us.