About
Patrick Jerominek is a cofounder of BeeBack UG, building invoice-api.xhub — a REST API for e-invoicing (XRechnung, ZUGFeRD, Factur-X, Peppol). He focuses on developer tools and the technical side of the EU e-invoicing mandate, and writes about e-invoicing standards, API design, and GoBD/GDPR-compliant invoicing for developers.
Posts by Patrick Jerominek (11)
Three things a customer found in our API
A hash that is not a fingerprint. Documentation that says "points" where the renderer reads millimetres. An n8n node that swallows the field name. None of them was a bug in the narrow sense — and none was in any documentation, ours included.
E-Invoices from DocuWare: XRechnung and ZUGFeRD from Index Data, Without Rebuilding the ERP
If outgoing invoices sit in DocuWare as PDFs with index data, the e-invoice can be created there. How our DocuWare connector (beta) works, how the result gets back into the file cabinet and where the limits are.
Your Own Fields on an E-Invoice — Without Losing Conformance
Vessel name, job number, machine serial: data EN 16931 doesn't know but your customer needs. Why a hybrid e-invoice has two layers — and where the boundary actually runs.
From PDF Invoice to E-Invoice: What Our First Customer Pipeline Taught Us
A facility services company writes its invoices in Word and Excel and must send e-invoices from 2027. How we built a pipeline behind that with n8n and the invoice-api — without a language model, with seven mapping errors that only the real API call revealed, and three findings in our own API.
E-Invoicing Mandate 2025: n8n Automation for Small Businesses
Germany's e-invoicing mandate affects every business. How SMBs automate invoice creation for free with n8n and the xhub.io API — incl. ROI numbers.
Automatically Validate and Archive E-Invoices with n8n
Fully automated n8n workflow: receive e-invoices via email, auto-detect the format, validate and archive compliantly — with Slack error alerts.
Customize invoice templates via API: BlockTemplate tutorial
How to generate PDF invoices with logo, brand colors and dynamic VAT rows using JSON only. Incl. EN 16931 compliance and ZUGFeRD pitfalls.
Create XRechnung with n8n — Step-by-Step Tutorial
Learn how to automatically create XRechnung invoices with n8n and Invoice-api.xhub. From Google Sheets to validated XML — completely without coding.
Our Biggest Customer Is Ourselves: Dogfooding at xhub.io
invoice.xhub.io runs on the same API we offer developers. A dogfooding story about shared libraries, real validation and our own pitfalls.
E-Invoicing Mandate 2025: Complete Guide for Developers
E-invoicing becomes mandatory for B2B in 2025. Technical guide with code examples for XRechnung, ZUGFeRD, and Peppol. Implementation checklist included.
Automatically Validate E-Invoices with n8n
Automated invoice validation with n8n and Invoice-api.xhub: schema checks, error diagnosis and escalation — completely without code.