Connect apps

Path: Integration > Connect apps · tier official · system integration · narrative reviewed (checked by Opus)

Overview

This section is for developers who connect external services to Business Central using REST web services. It starts with an overview of the two ways to build APIs: API pages for read-write access and API queries for read-only access. A walkthrough then shows how to write a custom API page in AL.

The getting-started page covers authentication setup and trying calls with the Insomnia REST client. The service-to-service page covers unattended integrations with OAuth 2.0 client credentials. Two further pages cover day-to-day use: filtering OData calls and tips on headers and batch requests.

Start with the API developer overview, then the getting-started page to set up authentication and make a first call. Use the custom API page when the standard APIs do not expose the data you need.

Key points

• API pages support read-write operations. API queries are read-only and can span multiple tables. Webhooks are supported.
• Custom API pages in AL need APIVersion, APIPublisher and APIGroup. They also use properties such as ODataKeyFields, SystemId, EntityName, EntityCaption and EntitySetCaption.
• Relationships are modeled with parts and navigation properties. The deprecated ODataEDMType complex types should be replaced.
• Getting started covers Microsoft Entra ID (OAuth 2.0) and basic authentication with a web service access key, and testing with Insomnia.
• Service-to-service authentication uses the OAuth 2.0 client credentials flow, with a Microsoft Entra registration and the API.ReadWrite.All and Automation.ReadWrite.All permissions.
• Tips cover the Accept-Language header, OData $batch requests, transactional batches with Isolation: snapshot, and the Data-Access-Intent header with ReadOnly.
• Filtering follows Microsoft REST API guidelines for property-based and range-based filter expressions in OData queries.

Learn pages

• API developer overview: Use APIs to expose information from the database into versioned, OData v4 enabled REST web services.
• Developing a custom API: Learn how to develop a custom API page by using an AL extension and accessing it to retrieve responses and make updates through the API.
• Get started developing Connect apps for Dynamics 365 Business Central: Learn how to develop a Connect app for Business Central, including setting up Microsoft Entra authentication and exploring REST APIs with Insomnia.
• Tips for working with the APIs: Provides some tips about working with Business Central API.
• Using filters with API/OData calls: Learn how to use filters with API calls to get targeted information in return.
• Using Service to Service Authentication: Service-to-service authentication enables external services to connect as an application, without impersonating normal users.

Source: Microsoft Learn (CC BY 4.0). Descriptions are Learn’s own.