---
title: "Multi-device sync and offline billing — setup guide"
source: https://www.lskhata.com/integrations/multi-device-sync
category: "Sharing & data"
---

# Multi-device sync and offline billing

The phone is the source of truth at the moment of sale, and the server is told afterwards. That ordering is the whole design: a bill finishes because the phone says so, not because a network did.

## Before you start
- One Khata account. Staff get their own logins rather than sharing yours.

## Setting it up

1. **Sign in on each device** (You) — Phone, tablet, and the dashboard if you have access to it. They read and write the same account.
2. **Give staff their own logins** (You) — Create each staff member with their own permissions. An entry then carries a name, and you can disable one account the day somebody leaves without changing anyone else's.
3. **Offline work queues and syncs** (Automatic) — With no connection the app keeps billing, taking payments and moving stock, storing everything on the device. It sends up when the signal returns.
4. **Duplicates are guarded on sync** (Automatic) — A bill raised offline carries an identity of its own, so a retry or a flaky connection cannot post the same sale twice.

## What moves, and in which direction
- **Device → server** — Bills, payments, stock moves and expenses, as they happen or when the connection returns.
- **Server → device** — Everything other devices on the account have recorded.

## How to know it worked
- Put the phone in aeroplane mode and raise a bill. It should complete normally.
- Turn the connection back on and check the bill appears on a second device.

## What this does not do
- The web dashboard and staff portal need a connection — offline is a mobile-app capability.
- Sync is not backup. Devices agree with each other, and a deletion syncs too.
- Two people editing the same record at the same moment is last-write-wins, not a merge.

## When it does not work
- **A bill raised offline has not appeared elsewhere.** Open the app on that device with a connection. Queued work syncs when the app is open, not while it is closed.
- **Two devices disagree.** Open both with a connection and let them settle. If they still disagree, tell us what each shows — that is a bug, not a setting.

## Common questions

**How long can I stay offline?**

There is no built-in cut-off. That said, syncing daily is the sensible habit — a device that has been offline for a week is a device holding a week of records that exist nowhere else.

**Is my data backed up if I lose my phone?**

Anything already synced is on the server and comes back when you sign in on a new device. Anything raised offline and never synced was only ever on the phone. This is the reason to sync daily.