Rip-and-replace rewrites are seductive and dangerous. They concentrate risk into a single cutover and freeze the business while engineers rebuild the past.
Strangle, don't replace
We prefer the strangler pattern: route new capability through a modern layer while the legacy system keeps serving, then migrate slice by slice. Each step is reversible and independently valuable.
Measure before you move
Instrument the old system first. You cannot safely replace what you cannot observe. Baselines turn "it feels faster" into defensible numbers.
Done well, modernization is a series of quiet, low-risk wins — not a make-or-break weekend.