A Vue application rarely becomes hard to maintain overnight. It happens gradually: a component grows a fourth responsibility, a piece of state ends up duplicated in two places, a prop drills five levels deep. By the time the friction is obvious, the patterns are everywhere. Scaling Vue well is mostly about catching these slides early and having conventions ready before you need them.

Composition API as an organising principle

The Composition API's real value is not terser components — it is the ability to extract a feature's logic into a composable that can be tested and reused independently of any template. When a component starts juggling several concerns, that is the signal to pull each concern into its own `use*` function. The component becomes a thin layer that wires composables to markup.

  • Name composables for the capability they provide, not the component that first needed them.
  • Keep a composable's surface area small — return only what callers actually use.
  • Resist the urge to make every composable global; co-locate single-use ones next to their feature.

Let TypeScript carry the contracts

In a large codebase, types are documentation that cannot go stale. Typed props, typed composable return values, and typed stores let you refactor with confidence: rename a field and the compiler shows you every call site. The investment pays off most precisely where it is hardest to keep a mental model — the seams between features.

If a refactor makes you nervous, it usually means the types are not pulling their weight yet.

State that scales

Not everything belongs in a global store. Most state is local and should stay that way. Reach for a shared store only when state is genuinely cross-cutting — the current user, a theme, a cart. When you do, keep stores focused: many small stores are easier to reason about than one omniscient one, and they tree-shake better.

Boundaries beat cleverness

The teams that keep large Vue apps healthy are rarely the ones with the cleverest abstractions. They are the ones who agreed on clear boundaries — where data fetching lives, how components communicate, what a feature folder contains — and then held the line. Clever code is a liability when five other people have to change it next quarter. Boring, predictable structure is what scales.