Glossary

Lazy Loading

Lazy Loading is a deferred-loading pattern: a resource or data is loaded only when it is actually needed, not in advance. The opposite is Eager Loading (loading everything upfront).

In different contexts

Images — the browser loads <img loading="lazy"> only when it enters the visible area, speeding up the initial page render
ORM — related data is loaded with a separate SQL query on first access. Convenient for prototyping, but can trigger N+1
JS modules — dynamic import() loads code only when needed, reducing the initial bundle size
Infinite scroll — content is loaded in portions as the user scrolls

When to be careful

In ORMs, lazy loading is convenient during development but dangerous in production: it is easy to miss how one property access turns into dozens of queries. Recommendation: in production code, always explicitly declare which relations are needed — through eager loading.