Tech specs
Everything, spec'd out.
The exact standards, formats and infrastructure EnvoiOK is built on — for anyone who wants to check before they buy.
Platforms
- Windows
- Installer (.exe)
- macOS
- Notarized .dmg
- Linux
- .deb (Ubuntu/Debian) todayFlatpak on Flathub planned
E-invoicing formats
- EN 16931
- The European semantic standard for e-invoices
- Factur-X / ZUGFeRD
- Hybrid format — a human-readable PDF/A-3 with the structured XML embedded inside, so people and machines read the same invoice
- PDF/A-3
- Long-term archival PDF, used as the invoice's visual layer
- VAT (VIES)
- Intra-EU VAT number validation on invoices to EU business customers
PDF engine
- Rendering
- Qt6
QPdfView, PDFium engine - Manipulation
- pikepdf (qpdf-based) — merge, split, rotate, reorder, delete
- Editing model
- Non-destructive, in-memory — your original file is never mutated; changes write to disk only on Save As
- Compression
- Image downsampling (Pillow) and font subsetting (fontTools)
Signing & timestamping
- Signatures
- PAdES-B-B, using your own certificate
- Timestamping
- RFC 3161, via a third-party timestamp authority — the document's content is never transmitted
Office → PDF conversion
- Local
- Uses your installed office suite (LibreOffice or Microsoft Office) — nothing sent anywhere
- Server-assisted (optional)
- For .docx/.odt/.pptx when no local suite is installed≤ 20 MB per file · converted via LibreOffice headless · per-request temp directory deleted immediately after
Data & hosting
- Account data
- Encrypted at rest (Fernet); lookups via keyed HMAC hash — never stored or compared in plaintext
- Infrastructure
- Scaleway & netcup, servers in Nürnberg, Wien and Paris — EU only
- Licensing
- One licence per business, activates the number of PCs your plan allows; log out a device anytime to free a seat
Languages
- Interface
- English and French — full translationAdditional languages in progress
Open source
Built on the shoulders of open source.
EnvoiOK wouldn't exist without these projects — see the full list, with licenses, on the Security & Data page.
Includes Qt/PySide6, LibreOffice, pikepdf, pyHanko, Pillow, fontTools, factur-x, pypdf, WeasyPrint, mammoth and pdfminer.six.