ERP system integration: the complete guide

Business systems don’t talk to each other on their own. The e-shop doesn’t know what’s in stock, the sales rep can’t see invoices, and the accountant retypes orders by hand — in the evening, with mistakes. That is exactly what ERP integration solves. In this guide we cover what integration involves, the four routes that lead to it, what a typical project looks like, what it costs and which mistakes to avoid.

What is ERP system integration?

The ERP is the heart of the company — it runs the accounts, the warehouse and the invoicing. But a whole ecosystem gradually grows up around it: e-shop, CRM, POS systems, carriers, banks, reporting tools. Each of them holds a piece of the truth about customers and money, and until they are connected, people carry the data between them. Integration means the systems hand data to each other themselves — by clear rules and with error checking.

In practice, three situations come up most often:

• E-shop and warehouseAn e-shop order lands in the ERP by itself, the customer sees live product availability, and the invoice goes out after dispatch — without a single manual step.
• CRM and accountingThe sales rep sees a customer’s invoices and payment behaviour right in the CRM (say, Raynet) without needing access to the accounts.
• Reporting and AIERP data flows automatically into overviews and dashboards — and now you can also ask an AI assistant about it in plain language.

Four ways to connect systems

Whatever the brief, technically it always comes down to one of four routes. They differ in deployment speed, price and how well they hold up in day-to-day operation.

• APIs and web servicesThe systems’ official machine interfaces — mServer for POHODA, the REST API for ABRA Flexi. The cleanest route for writing data; the limits tend to be speed, feature coverage and sometimes licensing terms.
• Direct database readsFor reading (reporting, stock-level sync, AI queries) it is often fastest to go straight to the ERP’s SQL database. No paid add-ons needed and no load on the application — but writes never, ever go into the database.
• File exchangeXML or CSV exports and imports. The oldest route, works almost everywhere — but it is fragile: there is no feedback, and errors surface late.
• Integration platform (iPaaS)A layer between the systems that uses the previous three routes internally and adds what matters on top: ready-made connectors, field mapping, queues, monitoring and retries on error.

A one-off bridge, or an integration platform?

The most common dilemma isn’t “which API” but “who builds it and who will look after it”. A bespoke bridge — a script moving data from point A to point B — is quick and cheap to acquire. But integration isn’t a project that ends one day; it is a service that has to run every single day.

How an integration project runs

Good news: integration is no longer a months-long IT project. With ready-made connectors we are talking days to two weeks; with bespoke solutions, weeks. The process is always similar:

1. Agenda analysis. What should be synchronised (orders, invoices, stock…), in which direction, and which system is the “master” for which data.
2. Field mapping. What the items are called in each system. This is where most surprises come to light: VAT rates, units of measure, customer matching.
3. Connection and configuration. Getting the connectors and access up and running (API keys, IP whitelisting), setting up data transformations.
4. Test run. Edge cases are verified on a sample of data — cancellations, partial dispatches, foreign currencies, duplicate customers.
5. Live operation with monitoring. Go-live plus ongoing monitoring of errors and queues. An integration nobody monitors is just a postponed outage.

What ERP integration costs

Prices span a wide range, and scope is the main driver:

• An e-shop platform’s native bridge — typically hundreds of Kč per month. The cheapest start, covering only the basic agendas of a single platform.
• An integration platform — a one-off implementation priced by the number of agendas, plus monthly operation in the low thousands of Kč; monitoring and connector maintenance are included.
• Bespoke integration — from tens to hundreds of thousands of Kč for development, plus ongoing maintenance costs every time either system changes.

The price is driven up by the number of connected agendas, two-way flows, non-standard processes and data quality. For your specific combination of systems, we will prepare a quote.

The most common mistakes

• No “master”. When it isn’t clear which system is the authority for a given field, the systems overwrite each other’s data and nobody knows what to trust.
• Synchronising everything. Every extra agenda means extra complexity. Integrate what the business needs, not everything that can technically be transferred.
• No monitoring. Silence doesn’t mean the integration is running — it may just be standing still quietly. Errors must never be discovered by your customers.
• Underestimated data quality. Duplicate customers and inconsistent product codes are not fixed by integration — they are exposed by it.

What about AI? A new layer on top of integrations

Integration has historically meant connecting system to system. Since 2025 there has been a third participant: the AI assistant. Thanks to the MCP standard, Claude or ChatGPT can connect directly to the ERP and answer questions over live data — “how much does company ABC owe us?” or “prepare the VAT documentation”. MCP doesn’t replace classic integrations, it complements them: integrations keep data flowing between systems, MCP answers people. What it is and how it works is explained in a separate article.

Frequently asked questions