Comparison
Layered architecturevsTier vs layer
Layered architecture
the controller called the database directly and three people commented on the pull request.
Arranging code so that each layer may only call the one beneath it — typically interface, application, domain, infrastructure. It gives you a rule that can be checked rather than an aesthetic, which is why layering violations are one of the few design arguments a linter can settle. Layers stop paying when they become pass-through: four layers that each rename a field are ceremony, not structure.
Full entry →Tier vs layer
someone said three-tier and meant three folders, and someone else heard three machines.
A layer is a logical grouping of code; a tier is a physical place it runs. Three layers can live in one process and one deployable, and usually should — the classic three-tier picture put them on separate machines because that was how you scaled in the nineties. Keeping the two words apart is what stops a layering discussion turning into a deployment argument.
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