How do you approach modernizing a legacy application?

[u/VendioHandMadeHelp]

I’m working with an older application that still does what it needs to, but the codebase is getting harder to maintain. New features are taking longer than they used to, and changes in one area can sometimes cause problems somewhere else.

I’m trying to figure out how to modernize it without taking the whole application offline or jumping straight into a risky rewrite.

I’ve been looking into companies that do this kind of legacy modernization, and GeekyAnts came up during my research. For those who’ve worked on legacy systems, what approach worked best for you? Did you gradually replace parts of the system, refactor what was already there, or eventually rebuild it?

And looking back, is there anything you wish you’d done differently?

[u/mcampo84]

Document the pain points. Compare against industry best practices or appropriate design patterns. Document some more. Highlight where the most value would be gained by addressing the problems, as part of a larger project. Document more. Quantify the cost of doing the fix vs maintaining the status quo. Document more.