Category: Business CentralRead time: 7 MinsPublished on: 12 Jan 2026

Coupa Supplier Portal Integration with Business Central via cXML

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The Coupa Supplier Portal (CSP) is a free online portal where suppliers work with customers who use Coupa, allowing them to receive and acknowledge POs, submit invoices or credit notes, track invoice and payment status, manage catalogs and company details, and maintain required compliance documents.

As a supplier, you may want to integrate your ERP system with the Coupa Supplier Portal to enable seamless communication with your buyers. Automating the creation of Sales Orders, Sales Invoices, Credit Notes, and the transmission of Advanced Shipping Notices (ASNs) can significantly reduce the time spent on ERP operations.

Let’s explore how to approach the integration between Business Central and the Coupa Supplier Portal. While Coupa offers multiple methods for document exchange between systems, our focus here will be on integrating via CXML.

Business Central does not offer a built-in solution for integration with the Coupa Supplier Portal. Organizations often work with experienced partners offering Business Central consulting services to design, implement, and support secure cXML integrations without disrupting core ERP operations. However, this can be achieved by customizing Business Central and leveraging various Microsoft Office 365 tools and services, such as Power Automate, Azure Functions, and SharePoint, to facilitate the integration.

1. Common prerequisites for integrating business central with Coupa Supplier portal

  • The supplier must have an active CSP account, and the buyer’s organization must be connected to that account in Coupa.
  • The supplier profile must be fully configured with required details, including legal entity information, banking data, and tax details.
  • The necessary cXML channels (PO Delivery, Invoice Delivery, ASN) must be enabled. This includes obtaining the Coupa cXML endpoint URLs, shared secret, and the Sender/From/To identity values.

2. Challenges and Approach before integrating Business Central with Coupa portal

  1. Authentication

    cXML does not prescribe a specific authentication method such as OAuth or API keys. However, Coupa uses a Client ID and Client Secret for cXML exchanges because the documents are transmitted over HTTPS through Coupa’s API gateway, which adheres to modern security standards. These credentials, along with the agreed-upon identity values, must be included in the cXML file.

  2. CXML Protocol

    A deeper integration with Coupa enables the exchange of cXML documents between the two systems. cXML is particularly well-suited for suppliers that handle a high volume of purchase orders or rely on automated invoicing processes.

    cXML, or Commerce eXtensible Markup Language, is a protocol for exchanging e-commerce documents like purchase orders and invoices between businesses. It is an open standard, built on XML, that enables automatic and standardized communication between buyers' procurement applications and suppliers' systems, improving efficiency and interoperability.

    Business Central does not provide native support for cXML documents. However, because cXML is based on XML, it can be parsed within Business Central using standard XML document features. You can also develop custom logic to parse cXML files or validate them against an XSD.

    Similarly, you can generate cXML documents such as ASNs or invoices using Business Central’s standard XML functions. Any features that creates or processes cXML must comply with the cXML DTD specifications. If it does not follow these standards, the Coupa Supplier Portal may reject the document.

  3. Receiving Documents in Business Central

    One of the main challenges in integrating with the Coupa Supplier Portal is receiving cXML files into Business Central. Although Business Central provides flexible API capabilities, it requires OAuth authentication, something Coupa does not support for cXML exchanges. Because Coupa does not offer OAuth or similar authentication methods for cXML delivery, a middleware component is needed to accept documents from Coupa.

    To simplify maintenance during upgrades, use Microsoft 365 ecosystem tools. For example, you can set up an Azure Function to act as an endpoint that receives cXML files and stores them in SharePoint or Azure File Storage. From there, Power Automate can move the files into Business Central. Alternatively, the Azure Function can post the cXML directly to Business Central, reducing the number of components involved in the integration.

  4. Validate the cXML document

    Another significant challenge in Business Central is ensuring that the cXML file complies with the standards defined by cXML organization. The site provides DTDs that can be used to create or validate cXML documents. However, Business Central does not currently support validating XML files against a DTD. It does, however, support validation using XSD files. To address this, you can use third-party tools to generate an XSD from a DTD and then validate your cXML files against that XSD.

  5. Sending Documents to Coupa Supplier Portal

    If your buyer provides an endpoint, you can send validated cXML documents to that URL using the HTTP Client functions. Ensure that the cXML document is fully compliant before transmission, as Coupa may reject it for even minor deviations from the cXML standard. Additionally, verify that the shared secret and identity information included in the cXML file match the values configured on the buyer’s side.

    Architectural diagram showing the bidirectional data flow between Business Central and Coupa via a middleware connector, illustrating the 'Send' and 'Receive' pathways for documents like Purchase Orders and Invoices.
  6. Acknowledging and Logging communications

    cXML always provides acknowledgements for document exchanges. When receiving a file, you should confirm that the document has been successfully received. Maintaining logs of cXML communications and their acknowledgements can be very helpful for troubleshooting any issues that may arise.

Integrating the Coupa Supplier Portal with Microsoft Dynamics 365 Business Central using cXML enables suppliers to automate high-volume transactions while maintaining control, accuracy, and compliance.

A well-designed integration reduces processing time, improves data consistency, and strengthens collaboration between buyers and suppliers. For organizations operating in complex procurement environments, this integration supports growth without increasing operational risk.

Need help integrating Coupa with Business Central? Contact our experts to design secure, upgrade-safe cXML integrations using Azure, Power Automate, and best-practice ERP architecture.