Businesses end up with two ERPs for ordinary reasons: an acquisition, separate branches that chose different tools, or a migration that takes longer than planned. Integrating them is possible, but success depends on decisions made before any code is written.
1. Define what must be shared
You rarely need everything synchronized. List the specific objects, such as customers, products, prices, stock levels, sales orders or journal entries, and the reason each must move.
2. Decide the system of record
For every object, choose which system is the source of truth. Two systems both editing the same customer record is how conflicts and duplicates are born.
3. Map the data
Fields, codes, units of measure, tax treatments and identifiers rarely match exactly. A mapping document is the heart of the project.
4. Choose the sync pattern
- Real-time via API or webhooks when immediacy matters.
- Scheduled batches when it does not.
- One-way or two-way, depending on the system-of-record decisions.
5. Plan for failure
Networks drop, records fail validation, APIs change. Build retries, logging and alerts so failures are visible and recoverable.
6. Test with real scenarios
Test edge cases: returns, partial deliveries, price changes mid-order, duplicate customers. Then run in parallel before cutting over.