What code splitting is
Code splitting is a technique that breaks an application's code into smaller pieces, or bundles, that can be loaded separately as needed. Instead of delivering all of the application's code to the user in one large download, code splitting lets the application load only the code required at the moment, loading other parts later when they are needed. This helps applications start faster.
The problem it solves
Modern applications can contain a large amount of code, and sending all of it to the user at once can make the initial load slow. Much of that code may not be needed immediately, or at all for a given user. Code splitting addresses this by dividing the code so that only what is needed is downloaded first, reducing the initial amount the user has to load.
How code splitting works
With code splitting, the application's code is divided into multiple bundles rather than a single one. The application loads the essential bundle to get started, then loads additional bundles on demand as the user navigates or uses features that require them. This way, code is delivered in smaller portions over time, matching what the user actually needs.
Code splitting and lazy loading
Code splitting is closely related to lazy loading. Splitting the code into separate bundles is what makes it possible to lazily load parts of an application only when needed. Together, they let an app defer loading code for features or pages the user has not reached yet. The split bundles provide the pieces, and lazy loading controls when each piece is fetched.
Benefits of code splitting
The main benefit of code splitting is faster initial load times, because users download less code up front. It also avoids delivering code the user may never use. The trade-off is added complexity in how the application is built and loaded, and brief waits when new bundles are fetched. Used well, code splitting makes large applications feel lighter and quicker to start.
Why it matters
Code splitting is an important technique for keeping large applications fast to load. Understanding what code splitting is - dividing code into smaller bundles loaded on demand - clarifies a key web performance strategy and its link to lazy loading. For anyone interested in web development, it is a valuable concept to understand.
Related on Skillo
See also: What is lazy loading? Explained, What is JavaScript? Explained.
Sources
Published date reflects the original event date (2024-07-02). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.
Leave a Reply