Data Sync Setup Guide
Keep HM Praxis in step across the devices in your clinic. Sync runs peer-to-peer over your own local network, so your data is shared directly between your machines and never travels through our servers.
Multi-device sync is available on the Pro tier. Basic and Trial users run on a single device without sync. Upgrade to Pro to unlock sync.
Verify Pro Plan Subscription
Sync is available on the Pro tier only. Check your subscription status to confirm your plan.
If you're on Trial or Basic, upgrade to Pro to enable sync.
Activate License on the Primary Device
On your main device (the one that already holds the database you want to share), activate your license key if you haven't already:
- Open the application
- Go to Settings → License
- Enter your license key and click "Activate"
See the license activation guide if you need help.
Enable LAN Sync on the Primary Device
Once your license is activated, turn sync on:
- Go to Settings → Sync
- Toggle "Enable LAN sync" to ON
- Both devices must be on the same Wi-Fi or Ethernet network (the same subnet)
- The device begins announcing itself to other HM Praxis instances on the local network
Nothing is uploaded to the cloud. Sync stays entirely on your local network.
Sync is purely peer-to-peer over your local network. There is no relay server and no patient data is ever stored on our servers. If your devices cannot see each other on the LAN, sync cannot happen.
Discover Peers on the Second Device
On each additional device you want to sync:
- Install the application
- Activate using the same license key
- Go to Settings → Sync and enable LAN sync
- Wait for the discovered peers list to populate with the primary device
Each device listens for the others' announcements on the LAN and builds the peer list automatically.
Copy the Database and Verify Sync
Bring the second device up to date, then confirm live updates:
- On the second device, select the primary peer and click "Copy Database from Peer" (a one-time bulk transfer)
- Make a change on one device, for example create a test patient
- Within a few seconds the change should appear on the other device
- Check that both devices show "Connected" in their sync indicator
If sync isn't working, see the troubleshooting section below.
How Sync Works
Offline-First Architecture
All data is stored locally on each device first, so you can work completely offline. When devices are on the same local network with sync enabled, changes flow directly between them.
Discovery via UDP Broadcast
Each device with sync enabled sends a small UDP announcement on the LAN every few seconds. Other devices listen for those announcements and build the peer list automatically. Only devices in the same organization are added.
Direct Peer-to-Peer Connection
Once peers discover each other, they open a direct WebSocket connection between the devices over your local network to exchange changes. No data passes through our servers.
Conflict Resolution
If the same data is changed on multiple devices while offline, the app merges changes automatically using a last-write-wins strategy. Manual conflict resolution is rarely needed.
Incremental Changelog
After the one-time initial database copy, each change (create, update, delete) is recorded in a local changelog and pushed to connected peers, which apply it to their own database.
What Gets Synced
The following data is shared between the devices on your local network:
Primary Data
- Patients and clinical records
- Notes and documentation
- Treatment plans and progress tracking
- History and classifications
Scheduling & Billing
- Appointments and calendar events
- Invoices and payment records
- Services and inventory
- Billing history
Configuration
- Templates and forms
- Custom fields and categories
- Organization members and roles
Not Synced
- Local app settings (theme, window size)
- Temporary cache and logs
- Large image originals replicate separately, out of band
Troubleshooting Sync Issues
Sync Status Shows "Disconnected"
Confirm both devices are on the same Wi-Fi or Ethernet network. Try toggling LAN sync off and back on in Settings → Sync. Make sure your local firewall allows HM Praxis to send and receive on the LAN.
Changes Not Appearing on Other Devices
Verify sync is enabled on both devices and that each shows the other in its discovered peers list. Both devices must stay on the same local network. If a device just joined, complete the one-time "Copy Database from Peer" step first.
Initial Database Copy Taking Too Long
Bandwidth and database size determine how long the one-time copy takes. Keep both devices on the local network and the app open. After the initial copy, only incremental changes transfer, which is much faster.
Sync Error: "Authentication Failed"
Your license may have expired or been deactivated. Check your subscription status. Reactivate your license if needed.
Duplicate Records After Sync
This is rare but can happen if the same data was created on multiple devices while they were apart. Edit or delete the duplicate on either device and the change propagates. Contact support if you need help.
Firewall Blocking Discovery
Local firewalls or "client isolation" on guest Wi-Fi can block the UDP announcements and the device-to-device connection. Allow HM Praxis through the local firewall, and use a network that lets devices reach each other directly.
Advanced Sync Notes
Same Network Required
Sync only happens while devices share the same local network. There is no internet relay, so devices in different locations cannot sync until they are back on the same LAN.
Choosing the Primary Device
The primary device is whichever one currently holds the database you want to share. A new device pulls its first copy from that peer, then both stay in step automatically.
Image Originals
Thumbnails sync inline with the database, while full-resolution image originals replicate separately out of band so they do not slow down everyday changes.
Sync Indicator
The sync indicator in the app shows whether peers are connected and when the last change was exchanged, which is useful for confirming recent changes reached the other devices.
For reliable LAN sync:
- Keep the app open on at least one device to keep changes flowing
- Use a stable wired or Wi-Fi connection on the same network for the initial copy
- Regularly check the sync indicator to catch connection issues early
- Avoid making the same change on two devices while they are apart
- Keep both devices on a network that allows device-to-device connections
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