Pro tip: They really are making up their own job titles. Nobody really cares, so long as you can do the job you claim to. If you say "software engineer" but

Pro tip: They really are making up their own job titles. Nobody really cares, so long as you can do the job you claim to. If you say "software engineer" but can't do more than add jQuery plugins to a web form, they're going to politely tell you that the interview is over. If your resume says "senior software engineer" and you apply for a job that just needs someone to add jQuery to a form, they aren't even going to call you. So far as I'm concerned, the title only matters on your resume, and is just for getting the right kind of attention. On a resume, "developer" is going to speak to lower and mid-level developer jobs, and "engineer" is going to be for jobs where you have to spend significant amounts of time designing systems that need to be maintained for a long time. If you think you're up for it, go ahead and use it. If you misrepresent yourself on your resume, you'll either not get the job, or you'll fail at the job when you get it, so it's up to you to get it right.