I build and integrate electronic invoicing systems for Latin American tax compliance, with deep, production-tested experience in Colombia's DIAN platform — invoices, credit/debit notes, XML signing, and direct transmission to DIAN. I currently run a live DIAN e-invoicing service handling high transaction volume in production, so I know the real-world edge cases: certificate handling and digital signatures (XAdES), DIAN schema and resolution changes, contingency and retry handling, and secure credential storage. Beyond DIAN, I work across XML document integration, SOAP/REST web services, digital signatures and PKI, and backend development in .NET Core, PHP and Python. If you're a software company, accounting platform, or ERP integrator that needs to connect to DIAN (or similar LATAM e-invoicing regimes) without building the expertise from scratch, I can get you there quickly and correctly.