Everything your address book has been missing
From search to sync to sharing — Kontax keeps your contacts organised, backed up, and always up to date.
Search that actually works
Type a name, phone number, email, company, label, or note — Kontax finds it instantly. Results are grouped by match type so you see exactly why a contact appeared. No more scrolling past irrelevant results or wondering if you spelled the name right.
Labels that organise, not just tag
Group contacts by anything that matters — family, clients, the five-a-side team — and filter your whole address book down to them in a tap. Labels stack, so one person can be both Work and VIP at once. Colour-coded badges keep every list scannable at a glance.
One address book, every device
Connect Google Contacts, Outlook, and any CardDAV account — iCloud, Fastmail, Nextcloud — and Kontax keeps them all in step. Edits sync both ways on a schedule, with a clear status on every connection so you always know what's current. One address book, mirrored everywhere you already work.
Share with family or your team
Invite the people you trust into a shared address book and everyone sees the same up-to-date contacts. Assign roles — owner, editor, or viewer — so you control who can change what. Updates appear live, so when one person fixes a number, it's fixed for everyone.
Your public contact card
Give out one short link instead of reciting your details. Your public card shows exactly the fields you choose, and anyone can save you to their phone with a single tap — no app required. Update your number once and every card you've ever shared updates with it.
See an exampleA developer API built for automation
Every contact, label, and address book is available through a clean REST API. Authenticate with a scoped key, then read or write contacts straight from your own tools, scripts, and integrations. Rate limits are generous and every response is plain JSON.
Read the API docsReady to tidy your address book?
Free forever for up to 100 contacts. Upgrade whenever you're ready.
Get started free