What proof holds up in a tax audit (and what doesn't)

In a tax residency audit there is one rule that changes everything: the burden of proof is on you. The tax authority doesn't have to prove where you were each day; it claims you as a resident and it's you who must dismantle that claim, day by day and on paper. The difference between a scare and a five-figure assessment is usually the quality of the file you can put on the table.

How the tax authority reconstructs your year

Before looking at what proof works, it helps to know what you're up against. An audit can cross-reference more sources than you'd expect: card movements and cash withdrawals, utility usage at your homes, road tolls and traffic cameras, municipal registration, your contracts and payroll, flight data and even your public activity on social media. With that, they build a narrative of presence. Your job is to have a better-documented narrative than theirs.

The evidence that carries weight

• A tax residency certificate from another country. The queen of evidence against the sporadic-absences rule: it formally proves another State considers you a resident. If your life is split, request one every year.
• Named tickets and boarding passes. They place a specific person in a specific place on a specific date. Tickets alone prove the purchase; the boarding pass proves the trip. Keep both.
• Hotel invoices and rental agreements. They prove whole stays with dates, not just a loose day. Better in your name and paid with your own card.
• Card movements and cash withdrawals. Hard to fabricate and easy to cross-check: an in-person payment at a Lisbon supermarket is hard data of presence. Their strength is in the continuous series, not the isolated entry.
• Contracts, municipal registration, schools and doctors. They don't prove specific days, but they build the context of where your life is — the "center of vital interests" that treaties examine.

The evidence that helps but isn't enough

• Your phone's geolocation. A continuous GPS log is valuable supporting evidence and increasingly accepted as reinforcement, but it is not conclusive proof on its own: technically it shows where a device was, not a person. Its real value is twofold: it gives you the exact map of your year so you know what to document, and it makes the rest of your file coherent.
• Screenshots and dated photos. Easy to manipulate, low evidentiary value. They work as support for other evidence, not as primary proof.
• Friendly witnesses. Statements from family or friends carry little weight: they are presumed to have an interest. An independent third party (a landlord, a client) carries somewhat more.

What doesn't work

Loose selfies, social media stories, "I was there, I swear" and memory reconstructions made two years later. Nor does the perfect archive… of the three months that suit you, with nine months blank: the gaps get filled against you (remember: sporadic absences count as presence unless you can prove residency in another country).

How to build your file without effort

The winning strategy is boring: continuous, varied, contemporaneous evidence. A record that feeds itself, every day of the year, with dated documents behind every stay. That is exactly what Daywhere does: it counts your days per country with background GPS and lets you attach the proof of each stay — ticket, invoice, receipt — in the moment, not two years later. When the letter arrives, your whole year will be in a report ready to hand over. And if you want to know where you stand today, start with the residency calculator.