Portuguese SMEs run on hard rules from the Autoridade Tributária (AT): every invoice must belong to a certified series, carry an ATCUD code and a QR code, be sequentially numbered without gaps, and be linked to the previous document through a signed hash chain. On top of that, the monthly SAF-T(PT) file must be produced in the AT's exact XML schema for e-Fatura submission. Stock ERPNext gives you Sales Invoices, IVA tax accounts and PDF print formats, but it has no concept of a certified series, no ATCUD, no RSA document signing, and no SAF-T(PT) generator. Bookkeepers end up patching gaps by hand or bolting on a second tool — which is exactly what the AT rules are designed to prevent.

ECOSIRE builds a proper Frappe app (its own module, not loose customizations) that plugs these gaps directly inside ERPNext. We add DocTypes for certified series and their sequential counters, and wire document signing into hooks.py on_submit/before_submit doc events so that at submission time each Sales Invoice, Credit Note and related document is hash-chained to its predecessor and signed with your AT-registered RSA private key. Custom fields carry the ATCUD (series-validation-code + sequential number) and the computed QR-code payload, rendered into compliant print formats. IVA is handled through pre-built tax templates and item tax rules for the standard, intermediate, reduced and exempt rates, with the correct exemption reason codes for zero-rated lines.

The SAF-T(PT) export is a whitelisted server method that assembles the full audit file — Header, MasterFiles (customers, products, tax table), and SourceDocuments (SalesInvoices with the signed hashes and ATCUD) — validated against the AT XSD before download. It is exposed both as a desk button and over the Frappe REST API so your accountant or an external filing tool can pull the file programmatically. Role profiles and permission rules keep signing keys and series configuration limited to finance roles, client scripts guard against manual tampering with numbering, and a scheduler event can pre-stage the monthly file so it is ready before the AT deadline. Everything targets ERPNext v15 and is forward-checked for v16.

Because this is build-to-order, you are not downloading a generic marketplace app and hoping it fits. After a short scoping call we confirm your legal series, IVA profile, chart-of-accounts mapping and AT certification details, then build and test the app against your data on a staging bench. You receive the installable source, install and configuration on your environment, documentation, a training session and a post-go-live support window. Typical delivery is one working week from confirmed scope, depending on how many document types and edge cases (self-billing, cash-VAT, retention) you need covered.