Rioko blog
Tax and technical guides
How to meet Portuguese tax obligations with full automation between Shopify or Stripe and InvoiceXpress, Moloni or Vendus.
Year End: The Invoice Series Checklist
What to prepare in December so January's first sale lands in the right series, with a valid ATCUD, and with no credit notes in the first days of the year.
ATCUD: What It Is, How to Read It, and What Happens When It Is Missing
Anatomy of Portugal's unique document code: where the validation code comes from, what each half means, where it shows on the invoice, and what to do when a document goes out without it.
Invoicing Stripe Payments in Portugal: Payments, Subscriptions and Refunds
A Stripe invoice is not a Portuguese tax document. How to turn Stripe payments, subscriptions and refunds into certified documents, with the right date and the right total.
Invoicing Shopify Orders in Portugal: The Complete Guide
What Shopify does not do on its own in Portugal, how to collect the VAT number at checkout, when to issue, and how to connect the shop to certified software without touching the checkout.
Intra-EU Reverse Charge: VIES, M16 and M40
How to invoice businesses in other EU countries without VAT: VIES validation, the right code for goods and for services, the mandatory wording, and the recapitulative statement.
OSS VAT: Selling Across the EU Without Registering in Every Country
The €10,000 threshold, registering for the One Stop Shop, the destination country rate, and what still gets invoiced in Portugal. A practical guide for online shops.
Portuguese VAT Exemption Codes M01–M99: Which One Each Sale Needs
The full table of the Portuguese tax authority's exemption reasons, what each code actually means, and how to pick the right one from the buyer instead of defaulting to M01.
How to Create an Invoice Series in InvoiceXpress
Step by step: creating a series in InvoiceXpress, filing it with the Portuguese tax authority by webservice, and getting the ATCUD validation code, including the trap of series that hold one sequence per document type.
How to Create an Invoice Series in Vendus
Step by step: creating an invoice series in Vendus, filing it with the Portuguese tax authority and getting the ATCUD validation code.
How to Create an Invoice Series in Moloni
Step by step: creating and filing an invoice series in Moloni, covering document sets, prefix, numbering and the ATCUD.
Invoice Series: What They Are and How to File Them With the Tax Authority
What an invoice series is, why document types must be kept apart, and how to file a series with the Portuguese tax authority to obtain an ATCUD.
ATCUD: How to Create a User at the Portuguese Tax Authority
Step by step: creating a sub-user on the Portal das Finanças with permission to file invoice series and obtain the ATCUD validation code.