[piva00]

Each EU country has its own rules about immigration.

A green card is probably equivalent to a permanent residence permit, those vary quite a bit between countries, and skills. Some countries might give a permanent residence in as few as 3 years, I believe quite a few have the 4 years threshold. Depending on what skills you have or how much you invest in the country you are moving to this timeline also shortens.

[agentcoops]

Generally continental Europe -- except the Scandinavian countries -- makes it relatively easy to get long-term residency and even a passport. The UK is considerably more difficult, but very easy to work in for an extended period of time (intra-company transfer visas etc).

[piva00]

Scandinavia had Sweden until yesterday's vote in Riksdagen, I moved here 10+ years ago, got my permanent residence after 4 years, citizenship after 5.

Rules have been changed now, citizenship in 8 years will become law on June 6th, also requiring language and cultural tests which weren't required before.

Continental Europe used to vary, Germany was stricter with 8 years to citizenship but permanent residence would vary depending on work skill and language skills.

[rmind]

Can you give some specific examples? I would say that, unless you have some additional qualifications (European ancestors, EU spouse and similar), the majority of EU countries actually don't make it that easy. Of course, it depends on your definition of "relatively easy".

[agentcoops]

Yes, it's never a trivial process, so a lot of work is certainly being performed by that "relatively": I have extensive personal experience with the UK immigration process and know of the US equivalent through the experiences of former colleagues back home. France, for example, is five years to a passport/naturalization. Germany is three years of skilled work to indefinite leave to remain. The Netherlands is five years to indefinite leave to remain. None of those examples require European ancestors, EU spouse etc, but generally it's easier if you have a university degree and work in the various fields most readers of hacker news do.

[rmind]

Well, naturalisation in most EU countries would involve some other requirements: language knowledge (you'd have to pass an exam) + civic/constitutional exam or integration test + naturally, no criminal record, etc + some countries are quite restrictive on dual-citizenship (i.e. they don't allow it for foreigners, meaning that you would need to renounce your original citizenship).

Visas and residence permits are, of course, easier.