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Multi-Device Sync

Use Vauchi on multiple devices with the same identity.

How It Works

All your devices share the same identity and stay in sync. Changes made on one device appear on all others.

graph TB
    subgraph "Your Identity"
        ID[Master Seed]
    end

    subgraph "Devices"
        D1[Phone]
        D2[Tablet]
        D3[Desktop]
    end

    ID --> D1
    ID --> D2
    ID --> D3

    D1 <--> |Encrypted Sync| R[Relay Server]
    D2 <--> R
    D3 <--> R

Linking a New Device

Prerequisites

  • Your existing device with Vauchi set up
  • The new device with Vauchi installed
  • Both devices online

Steps

  1. On your existing device, go to Settings > Devices
  2. Tap Link New Device
  3. A QR code appears (valid for 10 minutes)
  4. On your new device, install Vauchi
  5. Choose Join Existing Identity
  6. Scan the QR code from step 3

Both devices now share your identity and sync automatically.

Device Limits

  • Maximum: 5 devices per identity
  • Minimum: 1 device (your primary)

If you need to add a 6th device, revoke an existing one first.

Managing Devices

Viewing Linked Devices

  1. Go to Settings > Devices
  2. See all linked devices
  3. Your current device is marked

Each device shows:

  • Device name
  • Platform (iOS, Android, Desktop)
  • Last sync time

Renaming a Device

  1. Go to Settings > Devices
  2. Select a device
  3. Tap Rename
  4. Enter a new name

Revoking a Device

If a device is lost, stolen, or no longer needed:

  1. Go to Settings > Devices on another device
  2. Find the device to revoke
  3. Tap Revoke
  4. Confirm the action

Warning

You cannot revoke your current device. Use another linked device to revoke a lost one.

A revoked device:

  • Loses access to your identity immediately
  • Cannot send or receive updates
  • Cannot be re-linked without starting fresh

How Sync Works

  • Changes sync automatically when online
  • Sync uses end-to-end encryption
  • The relay server cannot read your data
  • Offline changes sync when connectivity returns

What Syncs

Data Syncs?
Your contact card Yes
Your contacts Yes
Visibility settings Yes
App preferences Yes
Device-specific settings No

Sync Frequency

  • Real-time: When both devices are online
  • On app open: Pulls any pending changes
  • Manual: Pull to refresh or Settings > Sync Now

Migration

Moving to a New Phone

Option 1: Device Linking (Recommended)

  1. On old phone: Link the new phone as a device
  2. Wait for sync to complete
  3. On old phone: Revoke the old phone (optional)

Option 2: Backup & Restore

  1. On old phone: Create an encrypted backup
  2. On new phone: Restore from backup

Device linking is preferred because it preserves device-specific keys and ensures a clean handoff.

Troubleshooting

Sync Not Working

  1. Check internet connectivity on both devices
  2. Ensure both devices have the app open
  3. Try manual sync (Settings > Sync Now)
  4. Check that the device hasn't been revoked

Device Not Appearing

  1. Wait a few minutes for sync
  2. Restart the app on both devices
  3. Check the link code hasn't expired (10 minutes)
  4. Try generating a new link code

Security

  • Each device has its own keys derived from your master seed
  • Revoking a device invalidates its keys immediately
  • The relay server never sees plaintext data
  • Device-to-device communication is end-to-end encrypted