Tukukkk

There's this person online with whom I have only interacted a few times. They had asked me for a small favour, which I did. They then wanted to give me something in return as a thank you. They were going to post it, so they wanted my address.

I am countries away and I'm not used to mail, especially international mail. I hate that I'm paranoid like this when I genuinely look forward to their gift, but I need to know to what extent do I share my details?

In the end, it all comes down to trust. How much do you trust this person and how much do you want to give as far as details goes? That you're asking here tells me you're not really sure if you can trust this person. There are risks involved (such as real life threats or maybe a possible scam) but it is not easy to identify risks without knowing the full situation, as you explained it rather vaguely.

To me the whole situation sounds kinda phishy to be honest. Are you sure you didn't fall for a phishing or scam attempt by helping this other person?

Most countries do have PO boxes and other rent-able post solutions so you don't have to give out your own personal details.

Many countries' postal systems have general delivery by which you can receive a package held at a post office for you to pick up, without having to give the sender an address. This might be an option for you.

In order for anyone else to assess how risky the situation is, I think you need to elaborate more on your relationship with the sender and the favor you performed for them. The vague way you've stated it is a big red flag for scams, involvement in money laundering, etc. but it may be that you've just poorly stated the situation out of a wish for privacy. At the very least though you should mention (or at least reflect upon for yourself) whether you had any relationship with the person prior to their asking you for a favor and whether you expected to be compensated in any way for the favor.

The whole favour thing--which they initiated--sounds rather like a setup aimed at getting your personal info. So I would recommend being very cautious here, and graciously declining their offer. Ask them to "pass it on" or "pay it forward" or something. The more they demand to get your info, the more suspicious you have a right to be.

Just giving out the address is no problem, as long as you limit it to the address. Don't you have phone directories "white pages" or similar where you live?

Think about it, hundreds of people probably have your home address. Of course, any of them could send you something illegal, immoral etc but as long as you act reasonably (E.g., you open an envelope and there is something that looks like drugs in, as long as you immediately call the police and you live in a reasonable country, nothing will happen to you. Rather, you will be greeted as some local hero if some local paper hears of the story.) there won't be any problems.

Same goes for this situation.