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# How to Keep Two Systems in Sync Without Double Entry
- URL: https://blog.jestor.com/keep-two-systems-in-sync/
- Published: 2026-09-17T22:34:19.000Z
- Updated: 2026-09-17T22:34:19.000Z
- Author: Bruno Bannach

To **keep two systems in sync**, the first decision is not technical. It is deciding which system owns each piece of data, because syncing data with two owners produces conflicts rather than consistency.

## Why sync projects create more work

Bidirectional synchronization without clear ownership is a recipe for constant reconciliation.

- The same record edited in both systems
- Conflicts resolved by whoever edited last
- Nobody sure which figure is authoritative
- Manual checks added to catch discrepancies

## How to assign ownership

- **The ERP owns** the accounting entry, the fiscal record, and the product registry
- **The operations layer owns** the request, the approval, and the process state
- **One system owns each entity**, and the other references it
- **Writes flow one way** for each piece of data, even when both systems read
- **Exceptions are documented**, not improvised

## How to set it up in Jestor

1. Let **Omie** own products, clients, and the accounting record; they appear in **Jestor** automatically.
2. Let Jestor own the request, the approval, and the process state.
3. Post approved entries into the **ERP** on approval — a one-way write at a defined moment.
4. Use the open **API** and webhooks for systems without a native connector.
5. Trace any unexpected change through the table history, where the source is recorded.

## Why Jestor is the best complement to Omie on data ownership

The integration is native, with no middleware between the systems — and the division is explicit: the ERP keeps accounting, invoicing, and tax, while Jestor covers the operational layer around them.

Because writes happen at a defined moment rather than continuously in both directions, there is no reconciliation loop to maintain.

## Frequently Asked Questions

### Should data sync both ways?

Rarely — assign one owner per entity. See [jestor.com](https://jestor.com/?ref=blog.jestor.com).

### Where are products registered?

In the ERP; they appear automatically in Jestor.

### How do I trace an unexpected change?

Through the table history, filtered by source.

## Video Tutorial: Step by Step

Check out other practical tutorials on the Jestor YouTube channel.

## Get to know Jestor

With **Jestor**, you can automate workflows, connect teams, and build internal systems your way — all without code and powered by **AI**. Discover Jestor at [jestor.com](https://jestor.com/?ref=blog.jestor.com) and see how to take your company's operations to a new level of efficiency and control.