As others, I would not recommend a full rewrite. But first, I'd take apart some assumtptions: - this code generates more than 20 million dollars a year of rev

As others, I would not recommend a full rewrite. But first, I'd take apart some assumtptions: - this code generates more than 20 million dollars a year of revenue This is GOOD! Thsi means this project is important. There WILL be budget for this. You need to find out two things: 1. What is the PROFIT margin? 2. HOW does this generate revenue? If you can increase profits (or promise to) by either making it easier to generate more revenue (onboarding woes of new customers / sales UI, etc) or a bigger margin, you'll be golden. - it runs on PHP This is not necessarily bad, check ylour code wars at the entrance. - it has been developed for 12 years directly on production with no source control ( hello index-new_2021-test-john_v2.php ) THIS is one of the things that need to be remedied - source control NOW. Get a professional course on git for all devs, add some nice dinner for teambuilding. - it doesn't use composer or any dependency management. It's all require_once. This needs to be adressed. - it doesn't use any framework This needs to be adressed. - the routing is managed exclusively as rewrites in NGInX ( the NGInX config is around 10,000 lines ) This needs to be adressed!!!!!!! - no code has ever been deleted. Things are just added . I gather the reason for that is because it was developed on production directly and deleting things is too risky. Source control should take care of some. The rest is on you sitting with the product manager to find out WHAT is the core, what needs to be removed, what features need to be kept. (bunch of horrible code smells that ALL need to be adressed.) - team is 3 people, quite junior. One backend, one front, one iOS/android. Resistance to change is huge. OK... if the team is junior, you need to lead. And WTF is an iOS / Android developer doing in your team? - productivity is abysmal which is understandable. The mess is just too huge to be able to build anything. This business unit has a pretty aggressive roadmap as management and HQ has no real understanding of these blockers. YOu need to sit with business and make them understand the blockers, the challenges, the timelines, AND the opportunities that your solutins will bring. And post COVID, budget is really tight. No it is not. See above.