Software Developers and Architects
How do developers integrate e-invoicing compliance APIs into billing systems?
Developers integrating e-invoicing compliance into billing, ERP, or accounting systems must interface with format generation libraries, validation APIs, and transmission networks. The integration architecture typically involves: generating invoice data objects in the application, passing them to a compliance API or library for format generation and validation, and then transmitting the validated invoice to the appropriate network or portal.
What are the common API integration patterns for e-invoicing compliance?
Three primary integration patterns exist for e-invoicing compliance APIs:
- Embedded library: Import a compliance library directly into the application; format generation runs in-process
- Microservice: Deploy a compliance microservice alongside the billing system; call via REST API
- Third-party SaaS: Send invoice data to a SaaS compliance platform API; receive back validated documents and transmission confirmation
- ERP add-on: Use a pre-built ERP connector that adds compliance functionality without bespoke development
- Webhook events: Receive compliance status updates (accepted, rejected, cleared) via webhooks to update invoice status
Frequently Asked Questions
- What data must a billing system provide to generate a compliant Factur-X invoice?
- To generate a Factur-X invoice, the billing system must provide: supplier and buyer legal name, address, country code, and VAT number; invoice number, date, and currency; line items with description, quantity, unit price, and applicable VAT rate; subtotals by VAT rate; total amounts including VAT; and payment terms. Optional fields include purchase order reference, delivery details, and custom allowances or charges.
- How do developers handle e-invoicing schema updates without downtime?
- E-invoicing schemas update periodically (Peppol quarterly, country specs annually). Developers should implement versioned invoice generation that can support multiple schema versions simultaneously. Feature flags or configuration allow switching to a new schema version on a specified date without code deployment. Automated regression tests against known valid and invalid invoice examples verify compliance after each schema update.