Everything you need for private, flexible contact sharing.
Built around privacy — not convenience for advertisers.
2048-bit RSA-OAEP keys are generated and stored on your device. Encryption and decryption happen locally. The server stores only encrypted blobs.
Choose individually which data fields (name, phone, address, etc.) to share with each subscriber. Change your mind at any time.
Display your personal QR code so others can scan and add you instantly. Available in both the Android app and web client.
Subscribed contacts are automatically synced to the Android Contacts app under a dedicated Contastic account — no manual export needed.
Receive instant WebSocket notifications when someone subscribes to you or approves your subscription request.
Find other Contastic users by their publicly shared name or email. No phone number harvesting, no social graph.
Your private key is encrypted with PBKDF2+AES-GCM using your password and stored as an opaque backup on the server — only you can decrypt it.
Deploy your own server in minutes with Docker Compose. Traefik handles TLS termination and Let's Encrypt certificates automatically.
Store any standard vCard field: FN, EMAIL, TEL, ADR, ORG, TITLE, URL, BDAY, and more.
Use Contastic anywhere.
Native app built with Jetpack Compose. Requires Android 8.0 (API 26) or later.
Progressive web app built with React 19 and Material-UI. Works in any modern browser.
FastAPI backend, PostgreSQL database, Traefik reverse proxy. Runs on any Linux server with Docker.