InvoiceIn is an inbound e-invoice API that processes various electronic invoice formats through a single endpoint. It accepts XRechnung, ZUGFeRD, Factur-X, Peppol BIS 3, FatturaPA, and KSeF files, converting them into standardized EN 16931 JSON format. This eliminates the need for separate parsers and validation rules for different standards. Processing occurs in memory within 10 to 50 milliseconds per file, with no disk storage. The API provides JSON output and validation reports with plain language fix hints. Additional outputs include PDFs, HTML files, exportable CSVs, and DATEV files for SKR03 or SKR04 standards. Validation uses EN 16931 Schematron rules, XRechnung standards, Peppol BIS requirements, XSD schemas, and arithmetic checks. It handles hybrid PDFs by extracting embedded XML without disk writing. InvoiceIn supports multiple languages for validation hints and offers detailed rule explanations. Deployment options include cloud service or Docker container.
