I fairly regularly check in with companies to make sure that there postings are still relevant, and take down postings when they aren’t, so as far as I’m aware, all companies listed there are looking for developers. If you’d like me to confirm that a specific posting is still active, please email me at email@example.com.
If you are a developer looking to relocate to Japan from abroad, be aware that companies are extremely picky about who they’ll hire, and unfortunately will often not respond to applications that don’t catch their attention. If your application demonstrates that you’re a perfect match for the position (relevant professional experience, something that demonstrates that you’re “unique”, and good communication skills), expect an answer, otherwise it’s going to be a shot in the dark.
If you feel you’re a great match for a position, and have take the time to write a customized application that conveys this, I’d also suggest following up with the company if you don’t hear anything back. Sometimes applications do get missed, just because the person in charge of reviewing them is busy with something else (often with startups the CTO is directly reviewing applications, while juggling other things). A reminder email can help get your application to the top of their queue.