2 years in Portugal before I logged into the AT portal. You should probably log into yours.

For three years my consultant handled my IRS. Every January they'd send an email: "Any changes to your household? If not, we'll proceed as last year." I'd reply "no changes," and that was my entire involvement until June, when I'd review the final numbers and approve.

It worked. I have no complaints about the service. But this year I decided to do the e-fatura review myself, just to understand what was actually happening behind the login.

It took about 20 minutes. Most of my invoices were already categorized automatically. I just had to confirm which ones were business expenses and which were personal. The deduction categories were clearly displayed, with caps for each one. The whole thing was... straightforward.

And that's when it hit me: I'd been paying someone to manage a process I'd never actually seen. Not because it was hard, but because I never looked.

The system Portugal built is actually clever

Where I used to file my taxes, you kept your paper receipts, claimed the expense, and the tax authority checked later if it wanted to.

Portugal took a different approach. Every time you give your NIF at a purchase, that invoice gets registered automatically in the AT portal under your name. Without your NIF on it, the invoice isn't linked to you, unless you register it yourself afterwards.

This means two things. First, your consultant rarely misses a deduction AT already holds, though pharmacy items at the normal VAT rate count only if you flag them as prescribed. An invoice AT doesn't hold is invisible to them unless you registered it yourself. Second (and this is the part I hadn't thought about) you as the taxpayer have zero visibility unless you actually log in and look.

My consultant was logging into my AT portal, reviewing my e-fatura expenses, confirming the categories, checking my agregado familiar, and verifying my pre-filled deductions. All things I could see for myself. All things I never knew existed as separate steps with separate deadlines.

IRS is not something you do in June

This is the thing nobody tells you when you move to Portugal. The Modelo 3 submission window opens April 1 and closes June 30. That's when most people think about their IRS. But by June, four critical phases have already happened.

Here's what the full year actually looks like:

January: Year-end prep. Gather your documents. If you had foreign income, get your bank statements and foreign tax returns ready. If you're a trabalhador independente, pull together your invoicing records. This is also when you should check if anything changed in the tax rules for the year you're filing.

By the end of February: Agregado familiar. You can confirm or update your household composition on the AT portal until the end of February. Married this year? Had a child? Got divorced? This is the deadline. If you don't, the return AT pre-fills for you starts from last year's household. When you file a Modelo 3 yourself you declare your household, and whether you file jointly, on the form itself, so a miss here is not final.

By the end of February: e-Fatura review. This is what I'd been outsourcing for three years. You log into the e-fatura portal and review every invoice linked to your NIF. Some need manual categorization, the system couldn't determine if that pharmacy purchase was health or cosmetics. You mark what's deductible and in which category. If you're a solo entrepreneur, you also flag which expenses were business costs.

March: Deduction check. By 15 March, AT publishes the deductions it calculated from your e-fatura data, and they feed your Anexo H. You review these numbers. If the general family expenses or exigência de fatura figure looks wrong, you can file a complaint (reclamação) by 31 March. That complaint does not cover health, education or housing: for those, you declare your household's own totals when you file. The deduction caps are displayed right there, health, education, housing, general family expenses, each with a maximum amount.

April 1–June 30: Filing. Now you submit your Modelo 3. But if you handled the four phases before this one, filing is mostly just reviewing what's already been calculated. The heavy lifting is done.

By 31 July: Assessment. AT issues your nota de liquidação. You either get a refund or owe additional tax. Payment or refund is due by 31 August.

September–December: Quiet period. Your IRS cycle for this year is complete, unless you are a freelancer AT has asked for pagamentos por conta (due 20 July, 20 September and 20 December). The next one starts in January.

The cycle, not the event

Once you see it as a cycle, you realize June is actually the easy part. The decisions that affect your tax bill, household composition, expense categorization, deduction confirmation, all happen between February and March. By the time you sit down to file, you're confirming choices you already made.

My consultant knew this. That January email wasn't just politeness, it was phase one of a structured process they ran every year on my behalf. The e-fatura review, the household confirmation, the deduction check, all happening in sequence, all with AT deadlines, all invisible to me.

I don't think most people realize how much happens before filing season. I certainly didn't. And if you're handling your own IRS without a consultant, these deadlines can slip by without you ever knowing they existed.

The NIF question that suddenly makes sense

You know how every shop in Portugal asks for your NIF? And how some expats treat it as optional or even suspicious?

Once you've seen the e-fatura portal, the NIF request clicks. Every receipt linked to your NIF feeds directly into your deduction calculation. Skip the NIF at the pharmacy, and that health expense isn't linked to you in AT's system, unless you register the invoice yourself afterwards using its QR code. It's easy to forget, and the deduction may never get created.

The first year I moved to Portugal, I probably skipped my NIF on half my purchases. I didn't understand why it mattered. Now I understand it's one of the things that matters most for deductions.

What I'm doing differently now

This is the first year I'm filing my own IRS. I reviewed my own e-fatura. I checked my own deduction pre-fills. I now know what categories my expenses fall into and where I stand against the caps.

The process isn't complicated. Portugal designed a system where the data flows automatically, NIF to e-fatura to deduction calculation to pre-filled declaration. The infrastructure is solid. What was missing, for me, was a tool that guided me through the whole cycle, not just the filing in June, but the phases before it.

I looked for one. Couldn't find it. So I built it.