ERP and CRM integration: your systems, connected

Signs you need an ERP integration

The symptom is nearly always the same: people acting as the bridge between programs. Someone exports a CSV from the CRM, cleans it up and imports it into the ERP. Someone checks a courier's website and copies the tracking number into another system. Every manual step costs time and lets errors through, and those errors tend to surface late, once the customer has noticed. The most common signs:

• Online shop orders are keyed into Sage or Xero by hand every morning.
• The stock shown on your website does not match what is on the shelf.
• Sales staff ring the accounts team to ask whether a customer is on stop.
• The same customer exists twice, with different details in each system.
• A spreadsheet is updated daily just to move data from one place to another.
• Month-end takes days because orders, invoices and payments live in different places.

Xero, Sage, Business Central, NetSuite, Odoo: what each one exposes

The ERP you run shapes the integration more than anything else. Some offer a well-documented cloud API; others are desktop software where the integration has to run next to your data.

If you run Xero, our page on Xero integration covers the API, Custom Connections and typical flows; for Sage, see Sage 50 and Sage 200 integration. The summary below is the starting point we check, using each vendor's own documentation:

Off-the-shelf connector, iPaaS or bespoke integration

Many ERPs and online shops have ready-made connectors in their app marketplaces, iPaaS platforms such as Patchworks or APPSeCONNECT specialise in common pairings, and tools like Zapier, Make or n8n let you build flows without much code. If your case is simple and a connector does what you need, use it: it is cheaper and you will have it in days.

A bespoke integration makes sense when the connector cannot handle your rules (customer-specific price lists, different units of measure, several warehouses, VAT codes per line), when volume makes per-task pricing expensive, or when you need control and an audit trail over every record. Sometimes the answer is mixed: a connector for the standard part and a bespoke piece for what does not fit.

How a reliable integration is built

Moving a record from A to B is the easy part. The hard part is deciding what happens when things do not match. These decisions are agreed and written down before any code:

• Which system owns each field. For example, the ERP owns prices and stock; the CRM owns contact details.
• When data moves: as soon as a system reports a change (webhooks) or on a schedule, within each API's call limits.
• How records are matched: by account code, VAT number or SKU, and what happens to the duplicates that already exist.
• What happens on failure: who gets told, with what detail, and how a person clears the queue of pending items.
• How it is tested: first against demo companies or sandboxes, then with a period of close monitoring in live use.

Connecting your ERP to Claude or ChatGPT safely

Asking an AI assistant "which customers are over their credit limit?" is now realistic. Xero, for example, now runs an official Remote MCP server and also publishes an open-source one under its own GitHub organisation, so assistants such as Claude Desktop can read and create invoices, contacts and payments. Our Xero integration page covers both.

Safe does not mean handing the assistant your ERP login. It means a layer in between that decides which data it can read, under which user, which actions it may take and which need a person's approval, and that logs everything. Start read-only, add writes one at a time, and choose the AI provider and data location with UK GDPR in mind. Check the ERP's own terms too: Xero's updated developer terms, announced in December 2025, prohibit using data obtained through its APIs to train AI or machine learning models. We cover this in more depth under AI agents connected to your systems.

How we would run your integration

In discovery we make real test connections to your systems before committing to a schedule, so if your ERP cannot do something you find out before you sign, not halfway through. After that it is one fixed price per project, a working demo every two weeks with data genuinely moving between test systems, and documentation of every flow in a repository in your company's name. The full method is on our page about fixed price software development.