You can't cURL a Border
64 comments
·November 4, 2025apexalpha
I had no idea travel was this difficult for people who aren't EU citizens.
Wow, I'm almost annoyed on the authors behalf of how much hoops there are to jump through.
>To apply for British citizenship, you need to prove you were physically in the UK on your application date but five years ago. Not approximately five years, not that week—that exact day when you press "submit" on the form minus five years. Miss it by 24 hours and your application is reject after months of waiting, and you have to pay a hefty fee to re-apply.
That's a hilarious requirement. I wonder how that ended up in there.
317070
First, the author is actually wrong. The date is not 5 years before you submit, but is 5 years before the form is received by the home office! So there are a few days of uncertainty, depending on how fast Royal Mail was with the physical documents.
Additionally, I did a request for my information from the home office prior to filling in my form. After all, you have the right to request the information they have on you that will be used to verify your form. Kafka would be proud.
Let me tell you, Home Office doesn't have a clue where you were 5 years ago. It had approximately 50% of my trips, and frequently only had only one leg of the journey. Plane, ferry, train, sailboat, ... it didn't matter. It seems like they have not been keeping the information very well.
philipwhiuk
The point is not to produce a system where a software engineer can loophole the system. The point is to try to prevent people who aren't committed to the UK apply for citizenship.
Muromec
It's not even hard really, I did it lastyear. I book a visit to the city hall, they look into the address db and see when I registered the first time. I see exactlt the same thing myself when I login into the thing.
The official agrees with me on the appointment date to actually submit the application, that is after cutoff date.
I put a signature on one sheet of paper, pay a thousand and go my way. The thing takes 15 min tops.
But it's continental Europe, not UK
Terr_
Guessing it stems from "we need something dead-simple to evaluate that yields a definite yes-or-no answer, with no annoying variables."
I'm trying to think of some other reason they might want a specific moment rather than "pick your own instant within this span", but I can't think of anything. Even if it was to "make sure you aren't claiming the same time on two applications to different places", the person could have simply staggered the applications.
SecondHandTofu
The other reason is more mundane. There's been a lot of political incentive to reduce immigration for a long time, which means adding arbitrary friction to increase the effort of applying and decrease the number of successful applicants.
Whether this is _effective_ is a different question, but certainly it's gotten a lot harder in recent decades, even pre-Brexit.
neximo64
This is actually standard for other countries too
cm2187
My guess is that if you need to have been there for 5y, you need to have a way to tell when that 5y starts. I presume it only matters if you apply the day after 5y. When I applied I had been in the UK for over 10y, provided 10y worth of proof of address, and the issue never came up.
jeroenhd
It depends on where you're going and what you're doing.
A lot of this faff isn't relevant if you're not applying for any visas or citizenship. Which is most people, most of the time.
The obvious solution to most of these problems for most people is "don't cut it close to any of the limits". If you enjoy traveling a lot, that's definitely a problem, but most people don't cross borders often enough to run into this many corner cases.
This is only a small peek into the awful bureaucracy that will hit Europe if extreme right wing parties keep gaining popularity across the EU. The extra calculations Brexit imposes, but not for every country you travel through!
miyuru
> A lot of this faff isn't relevant if you're not applying for any visas or citizenship. Which is most people, most of the time.
That’s true for many, but my passport isn’t very strong, so I still have to deal with a lot of paperwork for most transits.
thaumasiotes
Do you think applying on February 29 is allowed?
Note also that this isn't a travel requirement.
reisse
Ah, the classic programmer's mistake of treating complicated human interaction systems as a computer programs.
There is no State Almighty judging you to the last dot of absurdly complicated rules (well, in 99.99% cases when you don't actively look for trouble). Like, if you overstayed Schengen visa for one day because you messed up with counting entry and exit days, but used it otherwise for its intended purpose, the border officer likely won't even notice. Or for tax residence, a lot of countries I know just take what you say about your trips at face value - especially when there is no way to check it.
Just relax. If you don't know how to count your days in Morocco because they changed the time zone in an inconvenient moment, the officer evaluating your documents doesn't know that too. It's truth and best effort that counts.
Danieru
Overstaying a visa is a big deal. You should not be counting days or nights because you should not let yourself be in the country anywhere near the expiry of a visa.
nly
It's absolutely not best effort that counts.
I've heard many stories of people overstaying their visa in the US by e.g. one day, by way of a mishap or honest mistake, and subsequentially being denied visas or turned away at border control. The effects of this can go on for years and years... it's basically zero tolerance
FearNotDaniel
> buy a sausage roll at Greggs
If that's the first thing he thinks of while transiting through a UK airport, he deserves a citizenship, no questions.
BerislavLopac
The Life in the UK test certainly needs updating.
oarsinsync
Huge respect to the author for the details that have gone into this. I'd spent a week hammering at a Claude max 20x plan to try and build schengen 90/180 rolling window + tax residency in a couple of countries tracker... and that was hard work. I can only imagine how much effort has gone into this, to get all the details right.
It's unclear whether the author wrote all of this themselves, or if they outsourced a bunch of it to Claude. My experience with Claude was that it was terrible at writing code to do the math, even when I explained what the calculation needed to be, what the input was, and what the expected result was. It ultimately took starting a whole new project just to do the rolling window calculation, and then have that fed back in.
My biggest question for the author, if they happen to see this, is: how much manual testing validation did you do of the outputs the app produces? IE: Did you do the inputs + transformations = output calculations yourself as well, counting days on calendars, etc, to validate that the app is actually accurate? (That was the only way I developed any faith in solution I made for myself, which is way less impressive than your app). Regardless of whether you wrote the code yourself or not, a thorough test harness feels vitally important for an app like this.
gommm
I tend to find that for things like this that are really math heavy, it's usually better to create a DSL (or create easily readable function calls, etc) that you can easily write yourself instead of relying on AI to understand math heavy rules. Bonus points, if the rules are in an easily editable format, you can change them easily when they need to. It seems that was the path the author took...
And yes this kind of use-case is exactly where unit tests shine...
davedx
When I’ve worked on complex scheduling problems like that I use copious unit tests, they’re perfect for this kind of input->algo->output problem where algo has tons of edge cases.
Indeed, not using unit tests and instead trying to manually test all the cases sounds crazy to me!
caminanteblanco
It wasn't super obvious reading the article, but the app the author made is available for anyone to download.
https://drobinin.com/apps/residency/
If I wasn't on android and decidedly sedentary at the moment, I'd love to see how it works.
caminanteblanco
I just realized this was the same author who made the apple watch integration for their gym entry system, I loved their writing then, and I loved it here!
netsharc
Regarding the writing, I'm the opposite.. but I can't point out why I don't like it.
Maybe because the author is trying to sound sleek and sexy, "look at me, jetset international traveller", although the topic is so nerdy and dull, and the bragging feels off-putting to me.
(My opinion. Did I need to share it? probably not. Flag away if you think so)
davedx
No I agree, tone and context matters for technical writing too.
Digital nomads gonna digital nomad…
FinnKuhn
This made me appriciate the amount of visa-free travel my passport allows me on a whole new level. Figuiring these things out seems possible, but so inefficient and time consuming.
sanskarix
the weirdest part is how these systems still run like it's 1985. every country has its own database, none of them talk to each other, and you're supposed to manually reconcile everything.
I've watched digital nomads spend more time on visa spreadsheets than actually building their products. that's not a bug, it's a feature - the friction is intentional. less people get through.
what's wild is that someone can build this app faster than governments can modernize their own systems. maybe that says something about incentives. when your goal is to make things harder, not easier, tech debt doesn't matter.
qwertox
It seems that it has become quite popular that images don't expand anymore, when clicking on them. One needs to use the context menu "open in new tab" to get a properly readable image. Why?
wodenokoto
I’d say that’s pretty good behavior. It used to be common that images would expand in ways that would not allow you to zoom in mobile devices but also not allow you to open the image directly
bambax
There's some similarity between nationality and copyright: arcane, obscure, complex and mean rules that only benefit incumbents and punish everyone else.
I hope we will eventually get rid of both.
teiferer
At the rate things are going, even EU and Schengen, areas in which their citizens are blissfully unaware how nice they have it compared to outsiders, are going to come to an end. Far-right nationalists are on the rise over Europe.
evadne
This is an impressive article, & is incidentally why every sane set of rules has administrative discretion in its enforcement
If you're trying to engineer loopholes out of citizenship, you're going to get yourself pulled aside.
The whole point of these arbitrary rules is entirely to make this sort of shenanigans impossible but to let in people who are using the system for the purpose it was designed.