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Accounting system and CRM integration without losing data

While the accounting system and the CRM live apart, someone moves data by hand every day and sales and finance see different numbers. Here is how to connect them so the exchange does not collapse on the first error.

What goes where

DataFromToFrequency
Products, pricesaccountingCRMhourly or on change
StockaccountingCRM, websiteevery 10–15 minutes
Orders, dealsCRMaccountingon stage change
Invoices, paymentsaccountingCRMhourly

The core rule: every field needs one owner. If a price can be edited on both sides, sooner or later they diverge and nobody knows which is right.

Three ways to connect

  • Custom HTTP services — the most controllable: purpose-built methods for each exchange.
  • OData — fast to connect, but exposes raw data without business logic.
  • A middle layer in n8n — when more than two systems are involved or data needs transforming. The logic lives outside the accounting system and is easier to change.

What breaks in practice

Duplicate counterparties

The same company created twice under slightly different names. Match on a tax ID or external identifier, never on the name.

Connection drops

Documents must queue and deliver on reconnect, otherwise data is lost silently.

Repeat delivery

After a failure the exchange retries and creates a second document. The defence is idempotency: an external key per record, so a repeat updates instead of creating.

Rounding mismatches

Two systems round discounts differently. Decide where the final amount is calculated and pass it across rather than recalculating.

Non-negotiable: logs and alerts

Every exchange logged, every failure raising a Telegram alert. Without it, breakage is noticed a week later through missing orders.

FAQ

How long does it take?

A standard exchange: one to three weeks. Heavily customised configurations start with a survey.

What does it cost?

From €850 — see CRM to 1C integration.

Tell us about your setup and we will estimate it.

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