Suggest an editImprove this articleRefine the answer for “What is the difference between client-side and server-side data loading?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)The difference between **client-side** and **server-side** data loading in Next.js comes down to **where the request runs**, **when the user gets the data**, and **what HTML arrives in the browser**. **Key point:** server-side loading is for primary content, client-side loading is for dynamics and interactivity.Shown above the full answer for quick recall.Answer (EN)ImageThe difference between **client-side** and **server-side** data loading in Next.js comes down to **where the request runs**, **when the user gets the data**, and **what HTML arrives in the browser**. Let's go through it step by step, in plain language. --- ## Server-side data loading ### How it works 1. The user opens the page 2. The request reaches the Next.js server 3. The server fetches the data (from an API, a database, etc.) 4. The server builds the HTML **already with the data** 5. The ready HTML is sent to the browser ### What the user sees - The page displays with content right away - No "blank screen" and no waiting for data ### Pros - Faster first display of the page - Better for SEO - Secret keys can be used - Less logic and fewer requests in the browser ### Cons - Every request to the page can load the server - Not suited for interactive actions after the page has loaded ### When to use it - Content pages (catalogs, articles, feeds) - Data that's needed immediately - SEO-critical pages --- ## Client-side data loading ### How it works 1. The server sends **HTML without data** 2. The browser loads the JavaScript 3. The JavaScript makes a request to an API 4. The data arrives 5. The UI updates ### What the user sees - First an empty state / loading - Then content appears ### Pros - Less load on the server - Great for interactivity - Data can be refreshed without a page reload ### Cons - Slower first display of the data - Worse for SEO - Secrets can't be used ### When to use it - Forms - Filters - Likes, comments - Data that's updated often --- ## The main difference: the HTML **Server-side loading** -> the HTML arrives already with the data **Client-side loading** -> the HTML arrives "empty", the data loads in later --- ## What this looks like in Next.js In Next.js you can combine both approaches: - **Server**: - Server Components - `fetch` on the server - **Client**: - Client Components - `useEffect`, SWR, React Query A common scenario: - the server loads the page's main data - the client loads additional or frequently updated data --- ## Quick comparison | Criterion | Server | Client | |---|---|---| | Where the request runs | Server | Browser | | HTML | With data | Without data | | First render | Fast | Slower | | SEO | Excellent | Poor | | Secrets | Possible | Not possible | | Interactivity | Limited | Maximum | --- ### The key thing to remember - Server-side loading is for **primary content** - Client-side loading is for **dynamics and interactivity** - Next.js lets you conveniently **mix both approaches**For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.