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.
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.
100%
Private
No cloud
100%
Free
Forever
Interactive family tree visualization
See it in action
Your whole family, at a glance
Generations connected in one clean, interactive view—pan, zoom, and explore every branch.
Why Strom
Everything you need,
Everything you need,
nothing you don't
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.
Rich family records
Photos, life events, document scans, and proper source citations—everything a family chronicle needs, still in one portable file.
Free & open source
Free for personal use under MPL 2.0. Inspect the code, suggest improvements, or just use it with confidence.
And there's more
Grown-up genealogy, kept simple
- Photos & document scans on every person
- Life events — baptism, occupation, residence…
- Sources & citations with a per-tree catalog
- Printable family book with chapters & index
- Poster export (SVG / PNG / tiled print)
- Privacy filter hides living people in exports
- Relationship calculator (“second cousin…”)
- Adoptive & foster relationships, drawn distinctly
- Duplicate hints while you type
- Search filters with in-tree highlighting
- Undo / redo for every change
- Touch-friendly on phones & tablets
- Timeline view — lives as bars on a year axis
- Automatic versioned backups with one-click restore
- Family wizard — add a whole family in one form
- Family statistics — names, lifespans, birth months
- Anniversaries panel & "on this day" reminders
- Full offline mode — installs as an app
- Family collaboration by e-mail — share, fill in, merge back
- Ancestor fan chart (4–8 generations)
- Branch colours — paternal, maternal, descendants
- Save straight to a file on disk (Ctrl+S)
- Interactive guided tour for newcomers
- Change packets — reply with just what changed
- Deep consistency checks — dates, sources, attachments
- Map of the family's places — looked up once, then yours offline
- Slideshow — a hands-off flight through the tree, made for the TV
- Place suggestions from your own tree, spelling variants unified in a click
- Card density — compact, normal or detailed
- Make a new tree out of whatever you have on screen
Try it in one click — the app ships with sample trees (House of Tudor, Přemyslid dynasty).
Family teamwork, no cloud
Let the whole family fill in the tree
No accounts, no server. One file travels by e-mail — and comes back smarter.
1
Send it
Pick "Send to a relative", add a personal note, and e-mail the single file. Living people can be hidden automatically.
2
They add what they know
Your relative just opens the file — a friendly welcome invites them to fill in their branch and send the file back with one click.
3
Merge the reply
Open the returned file and Strom recognises it belongs to your tree — review their additions side by side and merge them in.
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.
Switching?
Bring your data from anywhere
Already have a tree on MyHeritage, Ancestry or FamilySearch? Export it as a GEDCOM file and import it here — people, families, dates, photos, sources and notes come along. No subscription, no person limit, no account.
MyHeritage
Site settings → Export family tree (GEDCOM). Free plans stop at 250 people — Strom has no limit. Export media too and attach the photos during import.
Ancestry
Trees → Tree settings → Export tree. Photos are not part of Ancestry's GEDCOM — download them separately and attach them during import.
FamilySearch
Use "Export tree" (or third-party tools) to get a GEDCOM of your branch. Your data then lives in your file — not in a shared public tree.
Why move?
Your family history shouldn't depend on a subscription. One free file, works offline, encrypted if you wish — and it opens in any browser, decades from now.
Start preserving your family history
Use Strom online or download for offline use. It's free for personal use.
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.
Support the project
Strom is free and will always be free for personal use. If you find it valuable, consider buying me a coffee to support ongoing development.