Ask HN: Take home interview project – is this ok?

If the interview project is obviously an exercise, and not something that will go into production for this enterprise, then it is fair game. They could have been a little more honest upfront telling you that the opportunity was closing for lack of budget, but nobody lost in the interaction, not even you: you got to perform an good programming exercise, and increased your own professional worth (granted only a small increase assumedly, but still). Or even, you could have fun doing it and that would be enough.

On the other hand, if you developped a feature that is not present in their product, that would fit (then you've got your hint), and if you see this feature appear in a couple of weeks or a few months in their product, then one would find indeed that you'd be justified to invoice them for the work done. Even if they made it do by hundreds of applicants and only selected the best one, it would still qualify as well as work, and they would have to pay everybody IMO. IANAL, so you know what to do.

If it is a company you want to work for then keeping in touch with the recruiter might make sense -- with the caveat that the recruiter is a company employee not a third party. If the recruiter is a third party then the process smells like common recruiter waste your time horseshit at best and a potential scam at worst.

The waste your time horseshit with third party recruiters runs along the line of using a potential candidate as the basis for negotiating a contract for placing them that contains a nice fee. If the company does not agree (and that may be by policy based on having in-house staff or existing contracts with external recruiters) then the candidate is told they did not get the job (or the job was not funded).

There are good recruiters and the best of them get retained contracts (paid to search). The next best get contingency contracts (paid to place).

Most recruiters have no contract. They scan help wanted ads on the internet, email people based on their resumes, and then pitch various candidates for positions with the hope that a company will bite and agree to their fee. The business model is more or less the same as email spam: the low cost of making contact makes high volume feasible and the high volume makes low conversion profitable.

Again, if it was a first party recruiter and you want to work for the company, then keep in touch because something else is likely to come up. But in any event, the best advice I have is to move forward.

Good luck.

I have less experience (~2 years), but I tend to use these projects to add to my projects page on my portfolio and I try to add something to each project that I don't already know, like Typescript or such.

That being said, I think they're a massive waste of time, especially positions that don't exist or that they already had decided against you. I've had two of them in the last two months both of which didn't lead to phone interviews.