Configure a multi-register setup

Multi-register mode lets several registers in the same shop share in real time the database: products, customers, sales, users, stock. Simple architecture: one register hosts the PostgreSQL server (the master), the others connect to it (the slaves).

Architecture

                      ┌─────────────────────┐
                      │   MASTER REGISTER   │
                      │   - AuraPOS         │
                      │   - PostgreSQL 18   │
                      │   192.168.1.10      │
                      └──────────┬──────────┘
                                 │ port 5432
              ┌──────────────────┼──────────────────┐
              │                  │                  │
       ┌──────▼──────┐    ┌──────▼──────┐    ┌──────▼──────┐
       │   SLAVE 1   │    │   SLAVE 2   │    │   SLAVE 3   │
       │   AuraPOS   │    │   AuraPOS   │    │   AuraPOS   │
       │ 192.168.1.11│    │ 192.168.1.12│    │ 192.168.1.13│
       └─────────────┘    └─────────────┘    └─────────────┘

⚠️ All registers must be on the same local network (LAN). AuraPOS does not support multi-register over the Internet (use a VPN if needed).

1. Install the master

On the register that will be master:

1. Run the AuraPOS installer
2. Check the option "Install PostgreSQL Server locally"
3. Check the option "Allow AuraPOS through Windows Firewall"
4. Complete the install

The installer installs PostgreSQL 18 and automatically creates:

• A user aurapos with password 7312
• A database aurapos
• A firewall rule on port 5432 (TCP)

On AuraPOS first launch, in the wizard, choose Multi-register — Master at step 3.

2. Give the master a fixed IP

This is critical: if the master's IP changes, slaves can't connect anymore. Two options:

• DHCP with reservation (recommended): on the router, reserve the IP address by associating the PC's MAC. The DHCP server will always assign the same IP.
• Static IP: configured manually in Windows (Settings > Network > Properties > IPv4).

Check the master's IP with ipconfig in cmd. Look for the IPv4 Address line of your adapter (e.g. 192.168.1.10).

3. Install a slave

On each slave register:

1. Run the AuraPOS installer
2. DO NOT CHECK "Install PostgreSQL" (slave has no local DB)
3. Complete the install

On first launch, in the wizard, choose Multi-register — Slave at step 3, then enter:

• Master IP: e.g. 192.168.1.10
• Database name: aurapos (leave default)

AuraPOS tests the connection. If it succeeds, the slave automatically downloads the master's config (payment methods, languages, etc.) and starts.

4. Verify synchronization

On the master, create a test product "TEST_SYNC". On the slave, open the product list → "TEST_SYNC" should appear within a second. Same for sales: a sale on a slave is visible immediately in the master's history.

Troubleshooting

"Connection refused" on the slave

Possible causes:

1. Master firewall blocks: check that the rule is properly created. On the master, in admin cmd:

   netsh advfirewall firewall show rule name="PostgreSQL AuraPOS"
   

2. PostgreSQL not started: services.msc → check that postgresql-x64-18 is running.
3. Master IP changed: re-run ipconfig and compare with what the slave has configured.
4. Different network: master and slave on different subnets (e.g. 192.168.1.x vs 192.168.0.x). Connect them to the same switch / SSID.

"Too many connections"

PostgreSQL is configured for 100 simultaneous connections by default. If you have more than 50 registers (rare!), increase max_connections in the master's postgresql.conf.

Slow synchronization

Check Wi-Fi quality between registers. For a shop with >5 registers, wired Ethernet is strongly recommended.

Current limitations

• No offline mode: if the slave loses connection to the master, it can no longer process sales. Offline resilience is planned for the stable version.
• No TLS encryption: the PostgreSQL connection is in clear text over LAN. Acceptable on a secure private network, avoid on public Wi-Fi.
• Backups only on the master: only the master register runs auto backups (slaves have no local .db file).

Tips

• Test the connection without installing a slave: from any machine on the network, run in cmd: psql -h 192.168.1.10 -p 5432 -U aurapos -d aurapos (password 7312). If it opens an aurapos=> prompt, your network and master are OK.
• Migration single → multi: if you start in single-register and want to move to multi later, your SQLite data is automatically migrated to PostgreSQL when changing mode in Settings > Storage.