Are there countries you cannot work with?

We can work with publishers and advertisers almost everywhere. The exception is people and businesses in countries under comprehensive international sanctions: we cannot open accounts for them or pay them, because the banks and payment providers we use are bound by those rules. Our compliance policy has the details.

Where your users are is a separate question. Offers are available in most countries, but some countries have far fewer than others — see "Why don't I see any offers?".