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ERP integration automation means connecting your ERP or accounting system to your other software, such as your web shop, CRM, planning tool or customer portal, through APIs so data flows automatically instead of being retyped. In practice you register an app or API user in the ERP, grant it access to exactly the data it needs, and build a service that reads and writes through the ERP's REST API with proper error handling. The technology is rarely the hard part; rate limits, messy master data and silent failures are.
The short version:
- Modern ERP and accounting systems expose REST APIs with token or OAuth authentication. Access should be scoped to exactly what each integration needs.
- Rate limits shape your design. Exact Online, for example, allows 60 calls per minute and 5,000 per day per company per app.
- Most integrations break not on the API but on duplicate records, empty fields and inconsistent codes.
- AI on top of your ERP works best with narrow, controlled actions: read broadly, write only through fixed, validated routes.
Why ERP integration automation matters
Your ERP is usually the system of record for customers, products, orders and finances. Around it sit a CRM, a web shop, planning or field service software, time tracking, email and spreadsheets. Without integrations, someone retypes the same customer, order or invoice into several systems. That costs time, introduces errors and leaves every system slightly out of date.
Integration automation fixes that by making data flow along defined routes: a won deal in the CRM creates a customer and sales order in the ERP, the invoice goes out from accounting, and the payment status flows back to the CRM so sales can see who has paid.
How ERP APIs work: two examples
Every ERP has its own API conventions, but the building blocks are similar. Two systems widely used in the Dutch mid-market illustrate the range.
AFAS Profit: connectors granted per integration
AFAS Profit, a Dutch ERP covering finance, HR, payroll, CRM and projects, offers the Profit REST API:
- An administrator creates an app connector for each external application. That's where you decide which connectors the application may use and where the token is generated.
- GetConnectors retrieve data. Each is an endpoint built from fields in a data collection, which you can compose and filter. You call it with a GET request.
- UpdateConnectors add (POST), modify (PUT) or delete (DELETE) records such as customers, sales orders or journal entries.
- Additional connectors cover reports, document items, files and images.
- The token is sent Base64-encoded in the Authorization header as
AfasToken <base64-string>. - Production, test and acceptance environments each have their own URL. Always build and test against test or acceptance first.
This model is strict, which is an advantage: an integration can only touch data an administrator explicitly enabled.
Exact Online: OAuth and hard rate limits
Exact Online, a cloud accounting and ERP platform, uses a REST API with OAuth 2.0. You register an app, the user authorizes access to their company, and your integration receives an access token that must be refreshed periodically.
The limits to design around:
| Limit | Value | Applies per |
|---|---|---|
| Per minute | 60 API calls | Company per app |
| Per day | 5,000 API calls | Company per app |
That sounds generous until you fetch the customer, items and stock separately for every order. Good integrations do three things: fetch master data in bulk and cache it, request only changes since the last sync, and read the rate limit headers to back off gracefully instead of hitting errors.
CRM and smaller accounting tools
CRMs like HubSpot and smaller accounting tools like Moneybird also provide well-documented REST APIs with OAuth or personal tokens. The patterns are the same; the edge cases differ per system. For simple, linear chains a no-code platform can work; our n8n vs Zapier comparison explains where the line sits.
The pitfalls that break ERP integrations
Whoever builds integrations meets the same problems over and over:
- Messy master data. Duplicate customers, spelling variations, empty tax ID fields. An integration that matches on name will create duplicates. Match on unique keys such as company registration number, VAT number or your own external ID.
- No idempotency. If a step fails and retries, it must not create a second order or invoice. Store which messages have been processed.
- Silent failures. An integration that fails without alerting anyone is worse than no integration. Log every error with enough context and alert on it.
- Rate limits and pagination. Pulling everything at once gets you throttled. Sync incrementally.
- Changes on the other side. A new mandatory field in the ERP or a changed pipeline in the CRM can break an integration. Retest after updates and keep a test environment.
- Unclear ownership of data. Which system is the source of truth for customer data? If two systems overwrite each other, you get an endless ping-pong. Pick one source of truth per data element.
- Expired tokens. A revoked or expired token stops the integration cold. Make sure someone gets notified, or you'll find out when a customer calls about a missing invoice.
Adding AI on top of your ERP
With solid integrations in place, you can put AI on your ERP data. Think of an assistant that answers "which customers have invoices overdue by more than 60 days?", or an agent that reads orders from incoming emails and creates draft sales orders in the ERP.
Principles that hold up in practice:
- Read broadly, write narrowly. Let the AI fetch data through read endpoints, but route writes only through fixed, tested actions with validation. Never give it unrestricted write access.
- Drafts, not final postings. Have a person approve before an order or journal entry becomes final, especially early on.
- Least privilege. Give the AI its own API user or app registration with only the permissions it needs, so the blast radius stays small if something goes wrong.
- Audit logs. Record which request led to which action. You need that for debugging and for accountability to your auditor.
There's a reason for caution. Developer discussions keep returning to the same point: ERP environments are full of incomplete or inconsistent master data, and AI agents perform worse on it than in a demo. An AI is only as reliable as the data it works on. Start with the integration and data quality, then add AI.
Protocols like MCP make it easier to connect AI models to business systems, but they bring their own security risks; see what MCP is. For what an agent actually is and does, read what is an AI agent.
Build, buy or no-code?
| Approach | Good for | Watch out for |
|---|---|---|
| Native connector or marketplace app | Standard scenarios both systems support out of the box | Limited control over mapping and exceptions |
| No-code platform | Linear flows, modest volume | Per-task pricing at scale, weak testing and error handling |
| Integration platform or unified API | Many standard systems, one interface | Abstractions can hide system-specific features |
| Custom integration | Core processes, multiple systems, custom logic, sensitive data | Needs developers and maintenance, but you own the code |
The right choice depends on how critical the process is and how many exceptions it has. A structured way to make that decision is in our business process automation guide.
Frequently asked questions
What is ERP integration automation?
ERP integration automation connects your ERP or accounting system to other business software through APIs, so data such as customers, orders, invoices and payment statuses flows automatically. It replaces manual retyping between systems and keeps every system up to date. A good integration includes error handling, logging and alerts.
How do I build an Exact Online API integration?
Register an app, have the user authorize access to their company via OAuth 2.0 and use the access token to call the REST API. Design around the limits of 60 calls per minute and 5,000 per day per company per app. Sync only changes since the last run and cache master data to stay within those limits.
What is the biggest risk in ERP integrations?
Messy master data is the most common cause of failure. Duplicate customers, inconsistent product codes and empty fields lead to duplicate records and wrong postings. Match on unique keys, pick one source of truth per data element and clean up data before going live.
Is it safe to give AI access to my ERP?
It can be, if you limit permissions. Give the AI its own API user with only the access it needs, route write actions through fixed, validated operations and let a person approve final postings. Log every action so you can trace what happened.
Next steps
Still retyping data between systems? The free AI scan shows which integration would pay off first. Airflows builds integrations between ERP, accounting, CRM and Microsoft 365 or Google Workspace, with error handling and logging, and you own the code. See our services for how we work.
Sources
- AFAS Help Center: REST API for developers (Dutch) (accessed September 26, 2026)
- AFAS: Profit API Concepts (accessed September 26, 2026)
- Exact Support: API rate limits (accessed September 26, 2026)
- Apideck: The Complete Guide to Exact Online API Integration in 2026 (January 28, 2026, updated May 13, 2026)
- Reddit r/SAP: Is your organization REALLY using Agents in SAP production? (2026)
- Reddit r/AI_Agents: I build AI agents for businesses, here's what actually breaks first (2026)
Builds AI agents, automations and custom software for businesses at Airflows.
