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Portugal · Agentic SaaS development

SaaS Development for Portugal: Billing, VAT and E-Invoicing

From 1 January 2027, small, medium-sized and micro-enterprises in Portugal that supply public bodies under the Código dos Contratos Públicos must issue electronic invoices, a duty large companies have had since 1 January 2021. For a SaaS founder in Portugal that is one line on a longer billing list: a 23% standard VAT rate at home, EU rules for customers abroad, and a Portuguese payment method that cannot renew a subscription on its own.

Curiosive works remotely from Ankara, Türkiye, as a studio building SaaS with AI coding agents under senior engineer review. Agents produce the CRUD screens, admin views, migrations and test suites. Engineers design the tenant model, the plan and entitlement logic, and the billing webhooks. Mainland Portugal runs two or three hours behind Ankara depending on the season, so most of a Portuguese working day overlaps with ours.

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VAT on selling SaaS from Portugal: 23% at home, OSS abroad

Article 18(1)(c) of the Código do IVA sets Portugal's standard VAT rate at 23% for supplies not covered by reduced rates. The legislative assemblies of the Azores and Madeira may set lower rates for supplies deemed made there, so a billing system that only stores the country can charge the wrong rate. Selling across the EU adds two more cases. Business customers in another EU country usually pay VAT at their own country's rate under the reverse charge, with several important exceptions. Electronic services sold to consumers are taxed in the customer's country, although below EUR 10,000 they may stay taxable where the seller is established, and the One Stop Shop lets a seller register in one EU country to declare that VAT. In the product this means storing country, region and VAT status per customer, with rates held as data rather than code. Confirm the treatment for your plans with an accountant.

E-invoicing in Portugal: CIUS-PT, SAFE and the 2030 EU standard

Electronic invoices to Portuguese public bodies follow CIUS-PT, the national data model based on the European standard EN 16931 (Portaria n.º 289/2019). Since 5 January 2026, the Autoridade Tributária e Aduaneira's free invoicing app on the Portal das Finanças can issue these B2G invoices and corrective documents through eSPap's FE-AP solution. For signing, the state-certified SAFE service lets a company's administrator, manager, director or attorney sign electronic invoices from integrated software; listed products include Moloni, InvoiceXpress, PHC GO, TOConline and Sage. EU rules point the same way. Under Directive (EU) 2025/516, invoices are to be issued electronically to the European standard from 1 July 2030, although Member States may allow other standards for domestic supplies, and invoices for reverse-charge supplies must be issued within 10 days of the chargeable event. So we keep invoice data structured from the first release, ready to pass to invoicing software, instead of producing PDFs that something has to parse later.

Multibanco, card checkout and payment authentication in Portugal

Multibanco works by voucher: the customer receives an entity and reference number and pays outside the checkout through online banking or at an ATM. Confirmation can take several days, and Stripe lists Multibanco as not supporting recurring payments. A SaaS product that offers it needs an explicit pending state, so access is neither granted before the money arrives nor withdrawn while a valid payment is in transit. Card checkout brings strong customer authentication instead. Under the PSD2 standards in Delegated Regulation (EU) 2018/389, applied since 14 September 2019, a provider may skip it for a remote payment of no more than EUR 30, but only while the payer's payments since the last authentication stay within a cumulative EUR 100 or five consecutive transactions. We treat the payment provider's events as the source of truth and write idempotent webhook handlers, so a redelivered event is never processed twice. Payment paths always get senior engineer review.

Tenant isolation and EU Data Act switching for SaaS vendors

Customers in Portugal buying SaaS also gain switching rights under the EU Data Act, which has applied since 12 September 2025 and whose recitals place SaaS among data processing services. Switching terms must sit in a written contract, with a notice period of no more than two months and a transitional period of no more than 30 calendar days. Until 12 January 2027 only reduced switching charges, capped at the costs directly linked to the switch, are allowed, and none after that. A service mostly custom-built for one customer is exempt from some of these duties, including the switching charge rules, if the customer is told before the contract which ones do not apply. Clean export of one tenant's data depends on the tenant model engineers design first: every row owned by a tenant, isolation enforced in the data layer, entitlements read from one place. Reveal Software (reveal.software), for a client in Romania, and PicKey (pickey.ai), with subscription billing for a client in India, are SaaS products we shipped.

Proof

Published project examples

Reveal Software

Reveal Software

Release Coach AI

Release Coach AI

Inspire Film

Inspire Film

Poppin

Poppin

Zing Coach

Zing Coach

ChurchBee

ChurchBee

AI-accelerated development
from$2,000
per month

Senior engineers building your product with AI coding agents: web, mobile, SaaS or browser extension, reviewed before anything ships.

  • Web, mobile, SaaS and browser extensions
  • AI-assisted delivery under senior engineer review
  • Scope and capacity agreed in writing, renews monthly

AI-accelerated development, billed monthly. We confirm scope, capacity and start date in writing before checkout.

Questions

The things people ask before starting.

What VAT rate applies to SaaS sold to consumers in Portugal?

The standard rate is 23%, which the Código do IVA applies to supplies not covered by a reduced rate. The Azores and Madeira may set lower rates for supplies deemed made in those regions, so a SaaS product needs the customer's region, not just the country, to charge VAT correctly at checkout and on renewal.

Can Multibanco be used for SaaS subscriptions in Portugal?

Not for automatic renewals. Stripe lists Multibanco as not supporting recurring payments, and confirmation can take several days because customers pay a reference through online banking or an ATM. It can still suit a manually paid plan, provided the product holds a pending state while the payment clears.

Does a Portuguese SaaS startup need e-invoicing for public sector customers?

Yes, from 1 January 2027 if it is a small, medium-sized or micro-enterprise supplying public bodies under the Código dos Contratos Públicos. Those invoices follow the CIUS-PT data model, and the tax authority's free invoicing app has been able to send them through FE-AP since 5 January 2026.

How much does it cost to build a SaaS product for the Portuguese market?

Building starts from $2,000 per month, the price of our one offer, AI-accelerated development, in US dollars. Each month's scope and capacity are written down once a discovery call has framed the product, so a first release with tenants, plans, VAT handling and checkout is sized against that monthly figure rather than a fixed package price.

Related pages

Solutions
Locations

Mobile App Development for Portugal: iOS and Android

Locations

Software Development for Portugal with Agentic Engineering

Services

Agentic SaaS Development: Multi-Tenant Subscription Products

Locations

SaaS Development for Romania: Billing, VAT and e-Factura

How it starts

What happens after you write to us.

  1. 01

    You describe the product

    One paragraph on what you are building, roughly when you need it, and who it is for. No brief, no form with fifteen fields.

  2. 02

    You get a reply within a day

    From the engineer who would do the work, not a sales team. If we are not the right fit we say so, and where possible we point you somewhere better.

  3. 03

    You get a scoped plan

    Scope, price and timeline in writing before anything is committed. You decide with the numbers in front of you.

No long contract to begin, no lock-in to our tooling, and the code is yours from the first commit.

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Ankara / Türkiye · Working across European and US time zones