Your address book.
Your rules.

Contastic is a self-hosted, end-to-end encrypted contact sharing platform. Your data stays private — always.

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Why Contastic?

Traditional address books sync your contacts to third-party servers. Contastic keeps you in control.

🔐

End-to-end encrypted

Private contact data is encrypted on your device before it ever leaves. The server only stores encrypted blobs it cannot read.

🏠

Self-hosted

Run your own Contastic server in minutes using Docker. No accounts with third-party companies required.

👥

Subscription model

You choose who can see your contact details and exactly which fields to share — per subscriber.

📱

Android + Web

Native Android app syncs contacts to your address book. Web client works in any browser.

How it works

Simple for users. Zero-knowledge for the server.

1

Register and generate your keys

When you sign up, an RSA key pair is generated locally in your browser or on your phone. Your private key never leaves your device.

2

Add your contact data

Fill in your name, phone, address, or any vCard fields you like. Mark each field as public or private.

3

Share your QR code

Others scan your QR code (or search by email) to find you and request access to your private data.

4

Approve and share selectively

Review subscription requests and choose exactly which private fields to share with each person. Data is encrypted client-side with their public key.

Ready to take back your address book?

Install the Android app or try the web client on our staging server.

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