Paraguay tax regime and possible SIFEN e-invoicing support

[learntheropes]

Hi Invopop/GOBL team,

We are working on P2Pagos, an open-source multi-rail payment and invoicing architecture focused first on Paraguay and Latin America.

We would like to contribute Paraguay support upstream to GOBL instead of maintaining a Paraguay-only local abstraction in our own codebase.

From what we understand, the clean split would be:

1. Add a Paraguay tax regime to GOBL:

   • country code: PY
   • currency: PYG
   • RUC / DV validation
   • VAT rates and categories
   • basic invoice normalization and validation
   • examples and tests

2. Treat SIFEN / SET e-invoicing as a separate conversion/delivery layer:

   • GOBL invoice → Paraguay SIFEN XML
   • digital signature
   • QR
   • SET submission
   • KUDE/PDF generation

For the SIFEN-specific layer, there are existing open-source TypeScript repositories from TIPS-SA that already implement several Paraguay electronic invoicing pieces and appear to be used in production. We are considering them as references for the Paraguay SIFEN mapping, XML generation, signing, QR, submission and KUDE generation.

Before starting the work, we would like to ask:

1. Would a Paraguay tax regime PR under regimes/py be welcome?
2. Is the recommended first scope limited to tax regime, validation, examples and tests, without SIFEN XML conversion?
3. For SIFEN / SET support, would you prefer:
   • a separate companion project,
   • an addon,
   • external integration outside GOBL,
   • or some other structure?
4. Are there existing country regimes we should use as the closest model for a first Paraguay implementation?
5. Is there anything specific you expect before accepting a new country regime PR?

Our goal is to keep the contribution small, legally accurate, testable and aligned with GOBL’s JSON-native design, while leaving the XML/SIFEN delivery layer separate if that is the preferred architecture.

Thanks.