EU and international businesses are increasingly mandated to send and receive structured e-invoices over the Peppol network, but ERPNext core stops at a PDF Sales Invoice print format. There is no native BIS Billing 3.0 UBL generation, no Access Point connectivity, no participant (SMP) lookup, and no way to ingest an inbound supplier invoice as a validated Purchase Invoice. Teams end up rekeying invoices into a portal or paying per-document fees to a disconnected middleware tool that never reconciles back to ERPNext. That gap is exactly what this connector closes.

ECOSIRE builds a proper Frappe app (for example peppol_connector) with its own module, DocTypes, and hooks.py doc events rather than a pile of loose customizations. Outbound, a doc_events hook on Sales Invoice on_submit renders a Peppol BIS Billing 3.0 UBL 2.1 XML document from the submitted invoice — mapping company and customer Address/Tax ID, item lines, UOM, tax templates and Tax Category to the correct UBL elements — validates it against the Peppol EN 16931 and BIS schematrons, and transmits it to your chosen certified Access Point over its API (AS4/REST, depending on provider). A dedicated Peppol Document DocType stores the transmission state, message ID, validation report, and the raw UBL for audit, with a status workflow (Draft → Validated → Sent → Delivered / Rejected).

Inbound is handled by a Frappe scheduler event (scheduler_events in hooks.py) that polls the Access Point for new documents, or a whitelisted REST endpoint the AP can push to as a webhook. Received UBL is parsed, schematron-validated, mapped to a draft Purchase Invoice (or held as a Peppol Document for review), and linked to the matching Supplier by their Peppol participant ID. Participant (SMP) lookup — confirming a trading partner is reachable on the network and which document types they accept — is exposed as a whitelisted method callable from a client script button on the invoice, so users verify a recipient before they hit submit. Everything is governed by ERPNext's permission model: a Peppol Manager role profile and per-DocType permissions control who can transmit, retry, or view raw payloads.

Because this is build-to-order, nothing ships as a blind download. We start with a scoping call to confirm your legal entity, country profile (BIS variants and any national CIUS such as the German or Belgian rules), your Access Point provider and credentials, and the exact Sales/Purchase Invoice fields to map. We build against a staging copy of your ERPNext v15 or v16 instance, run UAT with your real invoice data and sandbox Access Point, and only then install to production with a documented rollback. Typical delivery is one working week from confirmed scope. You receive the full source as a versioned Frappe app in a git repository you own, along with a post-go-live support window.