How to Create Custom API Endpoints in Business Central (Step-by-Step Guide)

Working with Microsoft Dynamics 365 Business Central and struggling to expose custom data or workflows?

You're not alone. While Business Central provides standard APIs, they often fall short when you need:

• Custom data structures
• Specific business logic
• Tailored integrations

That’s where custom API endpoints come in.

In this guide, we’ll walk through how to create custom API endpoints in Business Central and when you should use them.

What You’ll Learn

• What custom API endpoints are
• When to use them in Business Central
• Step-by-step approach to create them
• Common mistakes to avoid

Why Use Custom API Endpoints in Business Central?

Standard APIs are useful, but limited.

You may need custom endpoints when:

• You want to expose specific fields only
• You need custom business logic
• You are integrating with external systems
• Standard APIs don’t match your workflow

Custom APIs give you more control over how data is accessed and shared.

How Custom API Endpoints Work

At a high level:

1. Define a page object in AL
2. Expose it as an API
3. Publish it through Business Central
4. Access it via REST endpoints

Responses are typically returned in JSON format and can be consumed by external systems.

Step-by-Step: Creating a Custom API Endpoint

Step 1: Create an API Page in AL

Define a new page object with API properties:

page 50100 CustomerAPI
{
    PageType = API;
    SourceTable = Customer;

    APIPublisher = 'yourcompany';
    APIGroup = 'integration';
    APIVersion = 'v1.0';

    EntityName = 'customer';
    EntitySetName = 'customers';
}

This defines your custom API structure.

Step 2: Define Fields to Expose

Specify the fields you want available through the API:

layout
{
    area(content)
    {
        field(No; "No.") { }
        field(Name; Name) { }
        field(City; City) { }
    }
}

Only exposed fields will be accessible externally.

Step 3: Add Business Logic (Optional)

You can include validation or transformation logic depending on your use case.

This is useful when:

• You need calculated values
• You want to control data behavior

Step 4: Publish the Extension

Deploy your extension to Business Central.

Once published, the API endpoint becomes available.

Step 5: Test the API Endpoint

Access your API using:

• Postman
• Browser
• Integration tools

Example endpoint:

https://api.businesscentral.dynamics.com/v2.0/{tenant}/api/{publisher}/{group}/{version}/customers

Common Use Cases

• Integrating Business Central with CRM systems
• Syncing customer or order data
• Building custom dashboards
• Connecting external applications

Common Challenges

Incorrect API Configuration

Wrong entity names or versions can break endpoints.

Authentication Issues

OAuth setup must be handled correctly.

Limited Field Exposure

Only defined fields are accessible.

Versioning Problems

Changes in API versions can impact integrations.

Common Mistakes to Avoid

• Exposing too many fields unnecessarily
• Ignoring API versioning
• Not handling errors properly
• Skipping testing before deployment

Real-World Example

Let’s say you want to:

• Sync customers from Business Central to a CRM
• But only expose selected fields

With a custom API:

• You control what data is shared
• You ensure consistency
• You simplify integration logic

Pro Tips

• Keep APIs focused and minimal
• Use versioning properly
• Test endpoints thoroughly
• Document your API structure

Final Thoughts

Custom API endpoints in Business Central give you the flexibility to build integrations tailored to your business needs.

Instead of relying only on standard APIs, you can design endpoints that match your workflows and data requirements.

Want to Go Deeper?

If you're looking for a more detailed breakdown, check out this guide:

Business Central Custom API Endpoint Using AL | Satva Solutions

Learn how to create custom API endpoints in Business Central using AL language. Step-by-step guide for building, packaging, and deploying extensions.

satvasolutions.com