Archives
All the articles I've archived.
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Contract-to-Invoice Compliance: Catching Payment Term and Amount Mismatches Before Booking
How contract-to-invoice compliance checks work in practice — detecting payment term mismatches, recurring amount anomalies, and expired contract periods before invoices reach your accounting system.
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Parsing XRechnung and ZUGFeRD: UBL, CII, and Embedded XML Extraction
A practical guide to parsing XRechnung (UBL and CII) and ZUGFeRD invoices — format detection, StAX streaming, PDF XML extraction, and normalizing into a common model.
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Building a Deterministic Invoice Validation Pipeline in Kotlin
How I designed a deterministic, versioned validation pipeline for e-invoices using Kotlin and Spring Boot — covering rule versioning, idempotent processing, async job queues, and audit requirements.
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Correction Invoices and Storno in German E-Invoicing
How correction invoices and Storno (cancellations) work in XRechnung and ZUGFeRD — document chains, effective versions, and avoiding double-counting in accounting exports.
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How XRechnung Validation Works in Germany
A practical overview of XRechnung and ZUGFeRD validation in Germany — what 'valid' actually means, common errors, and why schema-compliant invoices still fail in accounting.