This is very common in Germany. I worked (and work) with several people across different employers that worked 2, 3, and (this is the most common variant) 4 days per week. All folks that worked 2 and 3 days, in reality though worked 7 days, because they were working on their personal project.

I've heard (but never checked, although I did find some resources: https://www.hensche.de/Rechtsanwalt_Arbeitsrecht_Gesetze_TzB...) it is mandated by law that employer (as long as it has more than 15 employees) must allow you that.

the law (or a more employee-friendly change to the law) came to pass last year (2019). The law gives employees much better chances to follow through, because it's now up to the employer to prove that part time is economically unfeasible for the employer. Before, if you wanted to go from full-time to part-time it was much more about hoping that your boss was understanding and having to argue etc. (although women with children usually had very good chances and usually in Tarif-Verträgen it is included that they can do part-time, so in big industries/companies it was easy for women already, at least those with children). I think in the Netherlands part-time is even more common; I've read somewhere that 50% of the people do part time - and most of them (unlike in the US) do it because they want to (80% of women there work part-time; 20% of men work part-time, so as a whole 50% do).

Is it that rare? I thought that it was pretty common in Europe.

In the Netherlands (where I'm from) I know loads of people on 4 day workweeks. It's often an option, and there's very few drawbacks for employee and employer.

The 20% paycut is pre-tax, so the real cut is a lot lower. It also lets employers hire a 5th person for every 4 80%s, so total productivity is likely higher due to people being happier, and there's more jobs total.

It's hard for me to imagine why tech companies wouldn't want to offer this to all their employees.

Over here in the Netherlands there is a law that makes it compulsory for the employer to agree to this kind of request, unless they can prove it is impossible to keep the business going otherwise (ie, "but we'd have to hire more people" is not a valid reason). There are a few minor restrictions like having had a permanent contract for at least six (I think) months, but otherwise any employee can request this.

https://europa.eu/youreurope/business/human-resources/employ...:

“Equal employment conditions

You must offer your part‑time staff the same employment conditions as full-time workers, including pay, leave, notice periods and other rights and benefits linked to their employment.

Modifying working arrangements

Whenever possible, you should try to accommodate requests from your employees if they want to change their working schedules, such as:

- transferring from full-time to part-time

- transferring from part-time to full-time

- increasing their working hours

You cannot dismiss an employee if they refuse to transfer from part-time to full-time work or vice versa.”

Working hours per week by country in Europe (includes some non-EU countries) at https://ec.europa.eu/eurostat/statistics-explained/index.php...

Europe is big and varied. Where I live (Croatia) I only know of one person who did it and it was only because he practically already accepted another job offer and the current company said "Alright, what can we do to keep you?" (and the salary scaled accordingly).

I'm sure there are other similar cases, but overall it's pretty rare here.

I'm in the UK, and have yet to come across anyone else doing it, though several of my European colleagues seem to be.

In the EU, employers have to, by law, consider reasonable requests for flexible working. If you work for a large company, that should mean most will have the option.

It's not hard to 'pull off'. You literally just have to request it.