Even if I trust you about the code being really bad, I'd still advise you to read this: https://www.joelonsoftware.com/2000/04/06/things-you-should-never-do-par

Even if I trust you about the code being really bad, I'd still advise you to read this: https://www.joelonsoftware.com/2000/04/06/things-you-should-never-do-part-i/ https://www.joelonsoftware.com/2000/04/06/things-you-should-... Joel makes it pretty clear that all codebases go through some kind of "maturing" where the quality is lacking, usually. It kind of made me change my opinion and approach to old codebases. Still, I think /u/freetime has the correct idea in not jumping into refactoring the first weeks of your job. Makes you look like a jackass (I made the same mistake at my current job). It might hurt, but I'd also advise to wait with improvements.