Modules after monolith slices: a Bangkok delivery story

Bangkok operations teams often standardize delivery while still running a monolith binary. We use that reality in classroom stories—not as inspiration porn, but as a constraint diagram. Participants draw module seams that align with ownership, not folder aesthetics. The essay walks through a anonymized migration where HTTP handlers stayed put while packages moved. We highlight the boring wins: import cycles removed, tests faster, ownership clearer. We also name the week where nothing shipped because a shared struct refused to budge. Readers looking for a silver-bullet framework will not find one. Instead we publish the checklist our mentors use when advising cohort projects: naming, error propagation, and observability hooks that survive the first refactor.