I needed to print 50+ personalized letters for my local fire fighter department. Most tools made this harder than it should be:

* Word Online (M365) doesn’t support mail merge * Google Docs never did * My old Apps Script broke

So I built a browser-based tool over the weekend:

* Upload a .docx template * Upload a .xlsx (or .csv) file with recipient data * Download a .docx with personalized letters — all locally in your browser, no cloud involved

It’s open source and privacy-friendly. Works well for quick offline letter runs or any task where email isn’t viable.

Live demo: https://mailmerge.somtoms.app/ GitHub: https://github.com/Somtom/simple-mailmerge

Maybe this helps folks out there with a similar problem. Would love feedback and ideas for improvement!