Single HTML file • Works offline

Your family story, beautifully preserved

Build and explore your family tree in your browser. No servers, no accounts, no tracking. Just you and your history.

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100% Private
No cloud 100%
Free Forever
You
Interactive family tree visualization
Why Strom

Everything you need,
nothing you don't

One file. That's it.

A single HTML file under 400kb. Download it, open it in any browser, done. No installation, no setup, no accounts.

Your data stays yours

Everything runs locally in your browser. No servers, no cloud, no tracking. Optional AES-256 encryption for exports.

Works everywhere

No internet required. Use it on a plane, in a cabin, or anywhere else. Your family history travels with you.

GEDCOM compatible

Import from Ancestry, FamilySearch, Gramps, and more. Export to share with anyone using the industry standard.

Just the essentials

Names, dates, places, relationships—nothing more. No photo uploads, no bloated features. A clean, text-focused approach to genealogy.

Free & open source

Free for personal use under MPL 2.0. Inspect the code, suggest improvements, or just use it with confidence.

Getting started

Three steps to your family tree

1

Launch

Click the button above. The app runs in your browser—no installation needed.

2

Build

Add family members, connect relationships, and watch your tree come to life.

3

Share

Export as a single HTML file. Send by email, save to USB, or share with family.

Start preserving your family history

Use Strom online or download for offline use. It's free for personal use.

Web app

Runs in browser. Install on your device for offline use.

Launch app

To install: Mobile → 'Add to Home Screen' in browser menu. Desktop → click install icon in address bar.

Recommended

Standalone file

Download a self-contained HTML file. Share via email or USB.

Download strom.html

Works on Windows, macOS, Linux, iOS, and Android. Any modern browser.

Important: Your data stays in your browser

Strom stores your family tree in your browser's local storage. This means your data is private and never leaves your device—but it also means you are responsible for backing it up. Use the Export function regularly to save your work as a file.

Tip: Export your tree after each session and keep copies in multiple places.