How would you design lazy loading and preloading in Angular routing?

Balances route ownership, initial bundle cost, likely navigation, authorization, and measurable user experience.

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TL;DR

I lazy-load feature routes or standalone components that are not required for the initial screen, using route boundaries that match product ownership. I preload only routes users are likely to visit soon or that need a fast transition, because preloading everything can consume bandwidth without improving the first interaction. A route guard may control navigation, but it does not make a downloaded bundle or client route an authorization boundary.

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Practice focus

Angular Router, lazy loading, standalone routes, preloading, route boundaries, and performance.

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Core answer first, then checkpoints toward a stronger answer.

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Core answer
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Overview
Lazy loading moves code out of the initial path; preloading decides which deferred routes are worth fetching early.
I lazy-load feature routes or standalone components that are not required for the initial screen, using route boundaries that match product ownership. I preload only routes users are likely to visit soon or that need a fast transition, because preloading everything can consume bandwidth without improving the first interaction. A route guard may control navigation, but it does not make a downloaded bundle or client route an authorization boundary.
Checkpoint
Stronger answer
Optional upgrade with examples, trade-offs, and sharper phrasing.
For example, an admin area and a large reporting feature are good lazy boundaries, while a tiny shared component is not worth a separate request by itself. I compare the initial bundle, navigation delay, cache behavior, and usage data before selecting no preloading, broad preloading, or a custom strategy. Route-level providers can keep feature services with the lazy route. Loading and error states still need a coherent UX when the chunk or its data fails.

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Common mistakesCandidateCommon mistakesMistakes that weaken the answer or signal shallow understanding.Open details

Details

Lazy-loading every small component without measuring the request overhead.
Preloading the entire application and calling it an optimization.
Treating a lazy route or guard as server-side authorization.

How would you design lazy loading and preloading in Angular routing?

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