Business Central API integration for the systems around your ERP
A Business Central API integration connects your ERP to web stores, logistics providers, CRM, payroll or in-house apps. It uses Microsoft's REST APIs. We design the data flow and build custom API pages where the standard ones fall short. We also secure everything with Microsoft Entra ID. Then we add the logging and retry logic that keep an interface dependable.
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What a Business Central API integration can use
Business Central online exposes a standard REST API that returns JSON. It covers the common business entities. These include customers, vendors, items, sales orders, invoices, purchase documents, journals and ledger accounts. An outside system can read these records, create new ones and change existing ones. The same business logic applies as in the user interface.
The API also supports bound actions, such as posting or shipping a sales order. You can filter, page and expand related records in one request. Each call targets one environment and company. Microsoft documents limits on request rates. A well designed integration respects them from the start.
Ask what the API covers →
- ✓Customers and vendors
- ✓Items and inventory
- ✓Sales orders and invoices
- ✓Purchase orders and invoices
- ✓Journals and ledger accounts
Custom API pages when standard endpoints are not enough
The standard API cannot know about your custom fields. It also cannot see tables that an extension adds. For those, we write API pages and API queries in AL. Each is a small object. It publishes exactly the fields an integration needs, under its own publisher, group and version. The standard endpoints stay as they are.
Custom endpoints also help shape data. A partner system may need one flat record that joins an order header with shipping details. We build that in AL. So the logic stays inside Business Central, and the calling system stays simple. We version each endpoint, so a later change does not break existing callers.
Scope a custom endpoint →- ✓Fields from your extensions
- ✓Tables the standard API omits
- ✓Combined or flattened records
- ✓Read-only reporting queries
- ✓Stable versioned contracts
Authentication for a Business Central API integration
Business Central online signs in API calls through Microsoft Entra ID with OAuth. For system-to-system traffic, we register an application in your tenant and grant it consent. Then we add it in Business Central as an application user with its own permission sets. Basic authentication with a web service access key is not available online.
Permissions deserve care. An integration that only creates sales orders should not read payroll journals. So we give each application the narrowest permission set that lets it work. We keep secrets in a vault, not in a configuration file. Separate registrations for separate integrations show which one made a call.
Check your API security →- ✓Entra application registration
- ✓Service-to-service OAuth flow
- ✓Narrow permission sets
- ✓Secrets stored in a vault
- ✓One registration per integration
Webhooks and events instead of constant polling
Asking every few moments whether anything changed wastes calls. It also reacts late. Business Central supports webhook subscriptions instead. An outside system registers an address. Business Central then notifies it when records of a chosen entity are created, updated or deleted. Subscriptions expire and need renewal, which the integration does by itself.
Business events go a step further. They signal that something meaningful happened, such as an order release. They can start a Power Automate flow or another subscriber. For high volumes, we combine notices with a scheduled catch-up read. That way, a missed message does not turn into missing data.
Design an event-driven flow →- ✓Webhook subscriptions per entity
- ✓Automatic subscription renewal
- ✓Business events for milestones
- ✓Scheduled catch-up reads
- ✓Power Automate as subscriber
How we deliver a Business Central API integration
We begin with a mapping document. It lists each field in the other system and its match in Business Central. It also says which side owns the field and what happens on a conflict. The build runs against a sandbox with realistic data. We test the awkward cases on purpose. These include duplicates, missing items, blocked customers, closed periods and calls that time out halfway.
The pitfalls are easy to predict. Integrations fail silently. Retries create duplicate orders. Nobody knows who should fix a rejected record. So we add logging, safe repeat calls and an error queue that a named person checks. You receive the mapping document, the source code and the monitoring setup. You also get steps for moving between environments.
Start an integration brief →- ✓Field mapping document
- ✓Integration source code
- ✓Error queue and alerts
- ✓Sandbox test evidence
- ✓Environment switch instructions
Business Central API integration FAQ
Does Business Central have a REST API?
Yes. Business Central online includes a standard REST API that works with JSON and covers the main business entities. It also supports custom API pages written in AL. You get webhooks for change notices and OData conventions for filtering and paging. So most integrations need no extra middleware to read or write core records. We check what your case needs first.
How do outside systems sign in to a Business Central API integration?
They use Microsoft Entra ID with OAuth. For unattended integrations, we register an application in your tenant and give it permissions inside Business Central. For an integration that acts for a person, the user signs in. The application then receives a delegated token. In both cases, no shared password sits in a script.
Can the API reach our custom fields?
Not through the standard endpoints, because those expose only standard fields. We publish a custom API page that includes your fields. Then they become readable and writable in the same way as the standard ones. Microsoft's own objects stay unchanged. That keeps your integration safe when Microsoft updates the base application.
Should we use middleware or connect directly?
A direct link suits a single, simple flow between two systems. When several systems swap data, the picture changes. So does a need to transform, queue and monitor messages in one place. Then an integration platform, such as Azure services or Power Automate, is usually easier to run. We compare both routes against your flows and explain which one we would choose.
What happens to a Business Central API integration at an update?
Microsoft versions the standard API. So existing calls keep working while a newer version arrives. Custom API pages are part of your extension. We test them against the preview of each release wave before your environment updates. As a result, you hear about a problem in a sandbox first, not from a failed order in production.
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