How do I get my dog to stop barking every time someone passes my apartment door?

How long has he been barking? Is he crate trained? Are you at home when he's barking and if so, what do you do to correct him from barking when he does this ?

Is he crate trained? If not, that's the place to start so you can put him in a quiet area of your apartment when you're not home, maybe have a radio/tv on to help block the noise. When you're home, don't let him hang out by the door. I don't know how old he is but if he's a young adult he's likely becoming more territorial about his home and the barking at noises is normal dog behavior. I teach my dogs to lay on a designated spot on command, usually an elevated bed is best. I keep dogs with potential behavior issues on a leash all the time, even in the house. This way you can direct him to where you want him to go. Make sure you no longer let him hang out or approach the door because allowing him to continue being there will only permit him to keep on barking/growling in that area.

This is something that needs to be addressed every time he barks and there is no guarantee that he won't do this when you are gone, even if you successfully curtail it while you're there. It's all about management and being consistent.