(*If you’d like to skip ahead and dive directly into the technical breakdown, jump to 1. Why React Server Components Were Introduced.) (*If you’d like to skip ahead and dive directly into the technical breakdown, jump to 1. Why React Server Components Were Introduced.) In the early 2010s, React revolutionized frontend development with its declarative component model and efficient virtual DOM diffing. What began as a simple view library soon became the backbone for large-scale single-page applications (SPAs). These SPAs predominantly used Client-Side Rendering (CSR), meaning the browser would download a JavaScript bundle, execute it, and construct the UI entirely on the client. This client-centric model was flexible and highly interactive, and it defined “modern” web apps for years. However, as applications grew more complex and feature-rich, the CSR approach started to show its cracks: Longer Time-to-Interactive (TTI): Hefty JavaScript bundles and client-side work meant users waited longer before they could actually interact with the page. Hydration bottlenecks: Converting server-rendered HTML into an interactive app (hydration) became a performance choke point, especially as the amount of dynamic content increased. Bloated bundles: Applications often shipped far more JavaScript than necessary, burdening browsers with code for features or content that could have been delivered more efficiently. Performance that doesn’t scale: The larger and more complex the app, the harder it became to maintain snappy performance across all devices and network conditions. Longer Time-to-Interactive (TTI): Hefty JavaScript bundles and client-side work meant users waited longer before they could actually interact with the page. Longer Time-to-Interactive (TTI): Hefty JavaScript bundles and client-side work meant users waited longer before they could actually interact with the page. Longer Time-to-Interactive (TTI): Hydration bottlenecks: Converting server-rendered HTML into an interactive app (hydration) became a performance choke point, especially as the amount of dynamic content increased. Hydration bottlenecks: Converting server-rendered HTML into an interactive app (hydration) became a performance choke point, especially as the amount of dynamic content increased. Hydration bottlenecks: Bloated bundles: Applications often shipped far more JavaScript than necessary, burdening browsers with code for features or content that could have been delivered more efficiently. Bloated bundles: Applications often shipped far more JavaScript than necessary, burdening browsers with code for features or content that could have been delivered more efficiently. Bloated bundles: Performance that doesn’t scale: The larger and more complex the app, the harder it became to maintain snappy performance across all devices and network conditions. Performance that doesn’t scale: The larger and more complex the app, the harder it became to maintain snappy performance across all devices and network conditions. Performance that doesn’t scale: Next.js emerged to tackle some of these pain points by introducing Server-Side Rendering (SSR), Static Site Generation (SSG), and other optimizations. These techniques improved initial load times and offloaded some of the UI rendering work to the server. But even with SSR and SSG, the fundamental issue remained: we were still over-delivering JavaScript to the browser. Fast forward to 2025. With Next.js 15 running on React 19, a new rendering paradigm has taken center stage: React Server Components (RSC). RSCs allow developers to seamlessly blend server-rendered and client-rendered components in a single React tree. The implications are significant. Static parts of the UI can now be delivered as pure HTML with zero JavaScript overhead. In other words, no client-side hydration is needed for those sections. Data fetching logic is also simplified by running inside server components, eliminating many unnecessary API calls from the browser. The result: leaner client-side bundles, faster interactions, and an application that’s far more performant and scalable. React Server Components (RSC) zero JavaScript overhead This article isn’t a surface-level review of RSC. When I set out to write about using Next.js effectively in 2025, it quickly became clear that React Server Components deserved a dedicated deep dive. What follows is a technically rigorous exploration of how RSC works under the hood, how to leverage it in a Next.js 15 project, and why it represents a fundamental shift in frontend architecture. By the end, I hope you come away with the same clarity and appreciation for RSC that I did through the process of researching and writing this piece. Intro: From CSR to RSC — How Rendering Evolved in React Intro: From CSR to RSC — How Rendering Evolved in React Over the past decade, the way we build React applications has fundamentally evolved and with it, the way we think about rendering. 🕰 A brief history of Client-Side Rendering (CSR) in React React gained its popularity through Client-Side Rendering (CSR) — a model where the browser downloads JavaScript, executes it, and builds the entire UI on the client. This approach gave developers full control over interactivity and state, and made it easy to build dynamic single-page applications (SPAs). Client-Side Rendering (CSR) However, CSR came with notable trade-offs: Slower initial loads, especially on mobile or poor networks Poor SEO for content-driven pages JavaScript-heavy bundles — even for pages with minimal interactivity A hydration step was required after HTML loaded, delaying time-to-interactive Slower initial loads, especially on mobile or poor networks Slower initial loads Poor SEO for content-driven pages Poor SEO JavaScript-heavy bundles — even for pages with minimal interactivity JavaScript-heavy bundles A hydration step was required after HTML loaded, delaying time-to-interactive hydration step For a while, these limitations were just “how things were.” Then Next.js changed the game. 🚀 How Next.js brought SSR and SSG to mainstream React development When Next.js entered the scene, it introduced server-side rendering (SSR) and static site generation (SSG) as first-class citizens for React. This marked a turning point: frontend developers could now choose how and when rendering occurred. Next.js SSR enabled pages to be generated per request, improving SEO and load speed for dynamic content. SSG allowed content to be prebuilt at deploy time, perfect for blogs, docs, and marketing sites. Incremental Static Regeneration (ISR) bridged the gap by allowing static pages to be updated post-deploy. SSR enabled pages to be generated per request, improving SEO and load speed for dynamic content. SSR SSG allowed content to be prebuilt at deploy time, perfect for blogs, docs, and marketing sites. SSG Incremental Static Regeneration (ISR) bridged the gap by allowing static pages to be updated post-deploy. Incremental Static Regeneration (ISR) This flexibility helped developers strike a better balance between performance, SEO, and developer experience. But even with SSR and SSG, there was still a lingering issue: we were still sending too much JavaScript to the browser — even for components that didn’t need to be interactive. we were still sending too much JavaScript to the browser 🧠 The rise of React Server Components (RSC) in 2025 With the release of Next.js 15 and React 19, we’ve entered a new era: React Server Components (RSC) are now a core part of how we build apps. Next.js 15 React 19 React Server Components (RSC) Unlike SSR, which still requires hydration and ships JavaScript to the client, RSC allows you to render components on the server — without sending any JavaScript to the browser at all. RSC allows you to render components on the server — without sending any JavaScript to the browser at all It’s a big shift: Components can now access server-side data directly Static content doesn’t require hydration You can mix server and client components in a single React tree, composing your rendering strategy per component Components can now access server-side data directly directly Static content doesn’t require hydration You can mix server and client components in a single React tree, composing your rendering strategy per component composing your rendering strategy per component RSC doesn’t replace SSR or SSG, it complements them, unlocking finer-grained control over performance, bundle size, and rendering behavior. complements them In 2025, RSC is a foundational concept that every senior React engineer needs to master. 1. Why React Server Components Were Introduced 1. Why React Server Components Were Introduced As React applications became more complex, the industry began to feel the weight of its success. While Client-Side Rendering (CSR), Server-Side Rendering (SSR), and Static Site Generation (SSG) offered different strategies for building performant web apps, each of them carried trade-offs that grew more apparent at scale. 🚧 Limitations of CSR, SSR, and SSG 1. Hydration overhead Hydration overhead Even with SSR or SSG, once HTML reaches the browser, React needs to “hydrate” the page — attach event listeners, reinitialize components, and effectively rebuild the app in memory. For large component trees, hydration can be a major bottleneck for Time-To-Interactive (TTI). 2. JavaScript bundle bloat JavaScript bundle bloat With CSR, every component, utility, and API call that’s part of the page must be sent to the browser — regardless of whether it’s interactive or not. SSR and SSG reduce this slightly, but most of the bundle still needs to be executed on the client. As apps grow, this leads to bloated bundles that slow down the user experience. 3. Disconnected data-fetching logic Disconnected data-fetching logic In the pre-RSC world, data lived outside the components that rendered it. You had to use getServerSideProps or getStaticProps (or call APIs in useEffect) to fetch data, then pass it into components via props. This separation added cognitive overhead and made code harder to co-locate and reuse. getServerSideProps getStaticProps useEffect 🧠 What problems RSC was designed to solve React Server Components (RSC) were created to address these growing pain points with a simple but powerful idea: let components execute on the server by default, and only send JavaScript to the browser when it’s absolutely necessary. let components execute on the server by default, and only send JavaScript to the browser when it’s absolutely necessary ✅ Eliminate unnecessary JavaScript Eliminate unnecessary JavaScript RSC allows components to be rendered server-side without shipping any of their logic to the client. If a component doesn’t require interactivity, there’s no need to hydrate or load its JS bundle at all. without ✅ Server-side data access within the component tree Server-side data access within the component tree RSC removes the artificial boundary between data fetching and rendering. Server components can use async/await to directly access databases, file systems, or APIs — co-locating data and view logic naturally, with no need for API routes or prop drilling. async/await ✅ Improve rendering efficiency and developer experience Improve rendering efficiency and developer experience By moving non-interactive logic to the server, developers can build lighter apps with smaller bundles and better performance. RSC also simplifies the mental model — you just write components, and let the framework handle where they run and how they ship. RSC doesn’t aim to replace SSR or SSG, instead, it complements them. It lets you think at the component level, not just the page level, about what should run on the server and what belongs in the browser. at the component level In short: React Server Components were designed to bring modern frontend development back to its lean, fast, and maintainable roots without compromising interactivity. In short: React Server Components were designed to bring modern frontend development back to its lean, fast, and maintainable roots without compromising interactivity. 2. Rendering Strategies in Next.js 15: RSC vs SSR vs CSR 2. Rendering Strategies in Next.js 15: RSC vs SSR vs CSR Next.js 15 offers developers a granular rendering model that goes far beyond traditional page-level strategies. With React Server Components (RSC) becoming a first-class concept, it’s essential to understand how they compare to two familiar models: Server-Side Rendering (SSR) and Client-Side Rendering (CSR). React Server Components (RSC) Server-Side Rendering (SSR) Client-Side Rendering (CSR) While SSG (Static Site Generation) is still valuable in specific cases, it can be viewed as a caching strategy built on top of SSR. In contrast, RSC vs SSR vs CSR represent distinct runtime rendering paths, and understanding them is crucial for making performance- and architecture-aware decisions in 2025. caching strategy RSC vs SSR vs CSR 💡 Before We Compare: What Do We Mean by "Interactive Component"? In the context of React and Next.js, an interactive component is any UI element that requires client-side JavaScript to respond to user input or browser events. interactive component requires client-side JavaScript to respond to user input or browser events This includes (but is not limited to): Buttons that update state on click Forms with validation or controlled inputs Dropdowns and modals that toggle open/closed Animations triggered by scrolling or hover Tabs, carousels, filters, sliders Components that use useState, useEffect, or useReducer Buttons that update state on click Buttons that update state on click Forms with validation or controlled inputs Forms with validation or controlled inputs Dropdowns and modals that toggle open/closed Dropdowns and modals that toggle open/closed Animations triggered by scrolling or hover Animations triggered by scrolling or hover Tabs, carousels, filters, sliders Tabs, carousels, filters, sliders Components that use useState, useEffect, or useReducer Components that use useState, useEffect, or useReducer useState useEffect useReducer If a component has event handlers, internal state, or relies on the DOM or browser APIs, it must run on the client. event handlers state DOM or browser APIs Interactivity = Browser-side behavior + JS event listeners + local state. Interactivity = Browser-side behavior + JS event listeners + local state. Understanding this distinction helps clarify why RSC exists: to avoid shipping JavaScript for UI pieces that don’t need to be interactive. why RSC exists 🧩 Rendering Models at a Glance Feature RSC (React Server Components) SSR (Server-Side Rendering) CSR (Client-Side Rendering) Render location Server Server Client JavaScript sent to browser ❌ None ✅ Yes ✅ Yes Requires hydration ❌ No ✅ Yes ✅ Yes Interactivity ❌ No ✅ Full ✅ Full Access to server resources ✅ Direct ✅ Via getServerSideProps ❌ Needs API calls When it runs On-demand or streamed Per request On load in browser Ideal use case Static or data-bound views Personalized or dynamic UI Interactive flows, local UX Feature RSC (React Server Components) SSR (Server-Side Rendering) CSR (Client-Side Rendering) Render location Server Server Client JavaScript sent to browser ❌ None ✅ Yes ✅ Yes Requires hydration ❌ No ✅ Yes ✅ Yes Interactivity ❌ No ✅ Full ✅ Full Access to server resources ✅ Direct ✅ Via getServerSideProps ❌ Needs API calls When it runs On-demand or streamed Per request On load in browser Ideal use case Static or data-bound views Personalized or dynamic UI Interactive flows, local UX Feature RSC (React Server Components) SSR (Server-Side Rendering) CSR (Client-Side Rendering) Feature Feature RSC (React Server Components) RSC (React Server Components) SSR (Server-Side Rendering) SSR (Server-Side Rendering) CSR (Client-Side Rendering) CSR (Client-Side Rendering) Render location Server Server Client Render location Render location Server Server Server Server Client Client JavaScript sent to browser ❌ None ✅ Yes ✅ Yes JavaScript sent to browser JavaScript sent to browser ❌ None ❌ None ✅ Yes ✅ Yes ✅ Yes ✅ Yes Requires hydration ❌ No ✅ Yes ✅ Yes Requires hydration Requires hydration ❌ No ❌ No ✅ Yes ✅ Yes ✅ Yes ✅ Yes Interactivity ❌ No ✅ Full ✅ Full Interactivity Interactivity ❌ No ❌ No ✅ Full ✅ Full ✅ Full ✅ Full Access to server resources ✅ Direct ✅ Via getServerSideProps ❌ Needs API calls Access to server resources Access to server resources ✅ Direct ✅ Direct ✅ Via getServerSideProps ✅ Via getServerSideProps getServerSideProps ❌ Needs API calls ❌ Needs API calls When it runs On-demand or streamed Per request On load in browser When it runs When it runs On-demand or streamed On-demand or streamed Per request Per request On load in browser On load in browser Ideal use case Static or data-bound views Personalized or dynamic UI Interactive flows, local UX Ideal use case Ideal use case Static or data-bound views Static or data-bound views Personalized or dynamic UI Personalized or dynamic UI Interactive flows, local UX Interactive flows, local UX 🔍 Think in Components, Not Just Pages Think in Components, Not Just Pages In earlier versions of Next.js, rendering strategies were applied at the page level. You had getServerSideProps, getStaticProps, and whatever you chose applied to the entire page. This made sense in a world where rendering happened all-or-nothing — either statically at build time, or dynamically on each request. page level getServerSideProps getStaticProps entire page But with React Server Components (RSC) and the app/ directory introduced in Next.js 13+ and standardized in 15, rendering is no longer a top-down, one-size-fits-all decision. It becomes a per-component concern that unlocks a new mindset. React Server Components (RSC) app/ rendering is no longer a top-down, one-size-fits-all decision per-component concern 🧠 A New Way of Thinking: Declarative and Composable Rendering This shift is more than an API change, it's a conceptual shift in how you architect your frontend. Declarative Declarative Instead of orchestrating how and where components are rendered manually, you now simply declare what each component does and what it needs — React and Next.js take care of the rest. how where declare what each component does and what it needs You don’t manually wire up API endpoints or pass props from SSR to components. You can just write: // Server Component export default async function ProductInfo() { const product = await db.getProduct(slug) return <div>{product.name}</div> } // Server Component export default async function ProductInfo() { const product = await db.getProduct(slug) return <div>{product.name}</div> } This component: Runs on the server Doesn’t send JS to the client Doesn’t require any getServerSideProps or API layer Is “just a component” — no extra abstraction needed Runs on the server Doesn’t send JS to the client Doesn’t require any getServerSideProps or API layer getServerSideProps Is “just a component” — no extra abstraction needed You describe the UI and its data needs declaratively, and the rendering engine figures out the rest. declaratively Composable Composable Different parts of your UI can use different rendering strategies — on the same page, at the same time, and with minimal overhead. on the same page at the same time with minimal overhead For example: // Product page layout <ProductInfo /> // Server Component (no JS, rendered on the server) <AddToCartButton /> // Client Component (interactive) <SimilarProducts /> // Static Component (SSG with revalidation) // Product page layout <ProductInfo /> // Server Component (no JS, rendered on the server) <AddToCartButton /> // Client Component (interactive) <SimilarProducts /> // Static Component (SSG with revalidation) These components live together in the same tree, but each one: Runs in a different environment (server, client, build) Uses only the data and code it needs Ships exactly what’s required to the browser — no more, no less Runs in a different environment (server, client, build) Uses only the data and code it needs Ships exactly what’s required to the browser — no more, no less To make this more concrete, I created a minimal demo that showcases how different rendering strategies can coexist on a single page. minimal demo 3. How React Server Components Work Under the Hood 3. How React Server Components Work Under the Hood React Server Components (RSC) are more than just a new rendering strategy, they fundamentally change how component trees are built, rendered, and transmitted. To use RSC effectively in production, it’s important to understand how it works behind the scenes and how it impacts the boundaries of state, interactivity, and data. how it works behind the scenes 🧱 Server/Client Boundary: A Split React Tree React applications using RSC are no longer fully rendered on the client. Instead, the component tree is split into two worlds: component tree is split into two worlds Server Components: Execute only on the server. No JavaScript is ever sent to the browser. Cannot hold local state or attach event listeners. Perfect for rendering static content and server-bound logic (e.g., DB access). Client Components: Must be explicitly marked with "use client". These are compiled into browser-friendly JavaScript and support full interactivity, local state, useEffect, and event handling. Server Components: Execute only on the server. No JavaScript is ever sent to the browser. Cannot hold local state or attach event listeners. Perfect for rendering static content and server-bound logic (e.g., DB access). Server Components Client Components: Must be explicitly marked with "use client". These are compiled into browser-friendly JavaScript and support full interactivity, local state, useEffect, and event handling. Client Components "use client" useEffect At build or runtime, React constructs a tree where server and client components coexist and stitches them together during render. 📍 What "use client" Actually Does "use client" When you add "use client" to a file, it marks that entire module and its exports as client-only. Behind the scenes, this instructs the Next.js build pipeline to: "use client" client-only Compile that file (and its dependencies) into a separate JavaScript bundle Exclude that component from being run on the server Treat it like a classic React CSR component with hydration logic Compile that file (and its dependencies) into a separate JavaScript bundle Exclude that component from being run on the server Treat it like a classic React CSR component with hydration logic This directive acts as a boundary marker between the two sides of the tree. All components above it can be server-rendered; all components below it must be rendered in the browser. boundary marker 💧 Streaming: Rendering in Pieces, Not All at Once RSC embraces streaming as a native rendering strategy. Instead of waiting for the full React tree to be built before sending it to the browser, the server streams serialized fragments of UI to the client as they become ready. streaming streams serialized fragments Server Components are rendered and sent as soon as possible Placeholders (e.g. via <Suspense>) fill in temporarily Client Components hydrate incrementally, only when they load Server Components are rendered and sent as soon as possible Server Components are rendered and sent as soon as possible as soon as possible Placeholders (e.g. via <Suspense>) fill in temporarily Placeholders (e.g. via <Suspense>) fill in temporarily <Suspense> Client Components hydrate incrementally, only when they load Client Components hydrate incrementally, only when they load ✅ How is this possible? RSC introduces a concept called selective hydration. When a Client Component is rendered within a Server Component tree, React inserts a placeholder (<div data-rsc-placeholder />) and defers hydration. Once the client has loaded the corresponding JS bundle: React lazily loads that specific component Finds the placeholder and stitches it into the live tree Hydrates it in isolation, without re-rendering the entire page React lazily loads that specific component Finds the placeholder and stitches it into the live tree Hydrates it in isolation, without re-rendering the entire page This design is decoupled and progressive: your app starts fast, and interactivity comes online gradually. decoupled and progressive <Suspense fallback={<LoadingDetails />}> <ProductDetails /> // Server Component </Suspense> <AddToCartButton /> // Client Component (hydrated later) <Suspense fallback={<LoadingDetails />}> <ProductDetails /> // Server Component </Suspense> <AddToCartButton /> // Client Component (hydrated later) ⚙️ Data Fetching and Code Splitting in RSC Another key “magic” of RSC: you can fetch data directly inside components with async/await — without relying on getServerSideProps, useEffect, or manual prop-passing. you can fetch data directly inside components with async/await getServerSideProps useEffect // Server Component export default async function Dashboard() { const stats = await getStatsForUser() return <StatsView data={stats} /> } // Server Component export default async function Dashboard() { const stats = await getStatsForUser() return <StatsView data={stats} /> } Why is this possible? RSC components run as real server functions, not as client-compiled modules They can access databases, internal APIs, file systems, or anything your server runtime supports The result is rendered HTML (not JS) and streamed to the client RSC components run as real server functions, not as client-compiled modules run as real server functions They can access databases, internal APIs, file systems, or anything your server runtime supports databases, internal APIs, file systems The result is rendered HTML (not JS) and streamed to the client Also: No hydration needed, since the result is static No loading UI logic in the component itself — everything resolves before it hits the browser No code for this component is sent to the client — unless nested inside a client boundary No hydration needed, since the result is static No hydration needed No loading UI logic in the component itself — everything resolves before it hits the browser No loading UI logic No code for this component is sent to the client — unless nested inside a client boundary No code for this component is sent to the client This significantly reduces boilerplate and bundle size, while keeping logic colocated with UI — a long-standing React goal finally realized at scale. 🚫 State, Hooks, and Lifecycle Considerations RSC does not support traditional React hooks like useState, useEffect, or useRef, because they don’t run in the browser. does not support useState useEffect useRef don’t run in the browser Feature Server Component Client Component useState ❌ ✅ useEffect ❌ ✅ useContext ✅ (if static) ✅ async/await ✅ ❌ (should wrap in effects) Event handlers ❌ ✅ Feature Server Component Client Component useState ❌ ✅ useEffect ❌ ✅ useContext ✅ (if static) ✅ async/await ✅ ❌ (should wrap in effects) Event handlers ❌ ✅ Feature Server Component Client Component Feature Feature Server Component Server Component Client Component Client Component useState ❌ ✅ useState useState useState ❌ ❌ ✅ ✅ useEffect ❌ ✅ useEffect useEffect useEffect ❌ ❌ ✅ ✅ useContext ✅ (if static) ✅ useContext useContext useContext ✅ (if static) ✅ (if static) ✅ ✅ async/await ✅ ❌ (should wrap in effects) async/await async/await async/await ✅ ✅ ❌ (should wrap in effects) ❌ (should wrap in effects) Event handlers ❌ ✅ Event handlers Event handlers ❌ ❌ ✅ ✅ This enforces a clean separation of responsibilities: Server Components: data and layout Client Components: interactivity and local state Server Components: data and layout Client Components: interactivity and local state React Server Components are designed to simplify your app. Once you internalize the boundary rules, the streaming model, and async data access, you can compose fast, personalized, and minimal-JS apps with far less boilerplate than before. compose fast, personalized, and minimal-JS apps 4. What’s the Best Practice? Combining RSC, SSR, and SSG 4. What’s the Best Practice? Combining RSC, SSR, and SSG One of the most common questions React engineers face in Next.js 15 isn’t “should I use RSC?” — it’s “how do I combine RSC with SSR and SSG in a maintainable, high-performance way?” “how do I combine RSC with SSR and SSG in a maintainable, high-performance way?” The beauty of Next.js 15 is that you’re no longer limited to one rendering strategy per page. Instead, you can now compose rendering strategies at the component level, applying the most appropriate approach to each part of the UI. compose rendering strategies at the component level This section introduces a practical framework for making that decision based on actual architectural needs. 🧭 Start with the Core Question: What does this component need? Ask these four questions for every component: Does it need to be interactive? ✅ Yes → Use a Client Component Does it need secure, request-specific, or real-time data? ✅ Yes → Consider SSR Can it be precomputed or infrequently updated? ✅ Yes → Prefer SSG Does it fetch server data but never need to run on the client? ✅ Yes → Use RSC Does it need to be interactive? ✅ Yes → Use a Client Component Does it need to be interactive? ✅ Yes → Use a Client Component ✅ Yes → Use a Client Component Client Component Does it need secure, request-specific, or real-time data? ✅ Yes → Consider SSR Does it need secure, request-specific, or real-time data? ✅ Yes → Consider SSR ✅ Yes → Consider SSR SSR Can it be precomputed or infrequently updated? ✅ Yes → Prefer SSG Can it be precomputed or infrequently updated? ✅ Yes → Prefer SSG ✅ Yes → Prefer SSG SSG Does it fetch server data but never need to run on the client? ✅ Yes → Use RSC Does it fetch server data but never need to run on the client? ✅ Yes → Use RSC ✅ Yes → Use RSC RSC 🧩 Example: Product Page Strategy Breakdown Here’s how a typical e-commerce prduct page might be composed using all three strategies: Component Rendering Strategy Reason ProductDetails RSC Fetched from DB, no interactivity, no need to hydrate PriceWithPersonalization SSR Depends on user session, dynamic per request AddToCartButton CSR Requires interactivity and local state RelatedProducts SSG (with ISR) Safe to cache at build-time, can revalidate every 24h or per tag StockStatusBanner RSC + streaming Frequently changing, streamed in with Suspense to not block TTFB Component Rendering Strategy Reason ProductDetails RSC Fetched from DB, no interactivity, no need to hydrate PriceWithPersonalization SSR Depends on user session, dynamic per request AddToCartButton CSR Requires interactivity and local state RelatedProducts SSG (with ISR) Safe to cache at build-time, can revalidate every 24h or per tag StockStatusBanner RSC + streaming Frequently changing, streamed in with Suspense to not block TTFB Component Rendering Strategy Reason Component Component Rendering Strategy Rendering Strategy Reason Reason ProductDetails RSC Fetched from DB, no interactivity, no need to hydrate ProductDetails ProductDetails ProductDetails RSC RSC RSC Fetched from DB, no interactivity, no need to hydrate Fetched from DB, no interactivity, no need to hydrate PriceWithPersonalization SSR Depends on user session, dynamic per request PriceWithPersonalization PriceWithPersonalization PriceWithPersonalization SSR SSR SSR Depends on user session, dynamic per request Depends on user session, dynamic per request AddToCartButton CSR Requires interactivity and local state AddToCartButton AddToCartButton AddToCartButton CSR CSR CSR Requires interactivity and local state Requires interactivity and local state RelatedProducts SSG (with ISR) Safe to cache at build-time, can revalidate every 24h or per tag RelatedProducts RelatedProducts RelatedProducts SSG (with ISR) SSG (with ISR) SSG (with ISR) Safe to cache at build-time, can revalidate every 24h or per tag Safe to cache at build-time, can revalidate every 24h or per tag StockStatusBanner RSC + streaming Frequently changing, streamed in with Suspense to not block TTFB StockStatusBanner StockStatusBanner StockStatusBanner RSC + streaming RSC + streaming RSC + streaming Frequently changing, streamed in with Suspense to not block TTFB Frequently changing, streamed in with Suspense to not block TTFB Each component is doing just what it needs to do — no more, no less. No full-page hydration, no global data fetching, no unnecessary JavaScript. just what it needs to do 📐 Design Best Practices for Combining Strategies ✅ 1. Start Server-First Design every component as a Server Component by default. Opt into interactivity ("use client") only when necessary. This keeps bundles smaller and simplifies testing. "use client" ✅ 2. Keep boundaries clear Use folder naming or filename suffixes to make boundaries explicit: /components /server/ProductDetails.tsx /client/AddToCartButton.tsx /shared/ReviewStars.tsx /components /server/ProductDetails.tsx /client/AddToCartButton.tsx /shared/ReviewStars.tsx ✅ 3. Embrace Suspense for progressive delivery Use <Suspense> to stream in non-critical RSCs without blocking the whole page: <Suspense> <Suspense fallback={<LoadingReviews />}> <ReviewList /> </Suspense> <Suspense fallback={<LoadingReviews />}> <ReviewList /> </Suspense> ✅ 4. Co-locate logic with components Don’t split data-fetching and UI across files unless necessary. In RSC, you can colocate async logic directly inside the component tree — the framework takes care of the rest. async ✅ 5. Use ISR (Incremental Static Regeneration) smartly For cacheable, high-traffic pages like blog articles or marketing sections, use SSG + revalidation: export const revalidate = 3600 // regenerate every hour export const revalidate = 3600 // regenerate every hour ⚠️ Common Mistakes to Avoid ❌ Using "use client" by default — you’ll end up with CSR all over again ❌ Fetching data in client components when it could be server-fetched ❌ Passing too much data between RSC and client components via props — instead, let client components be focused, isolated, and stateful ❌ Recreating SSR-style getServerSideProps logic inside RSC — no need, RSC is server-side ❌ Using "use client" by default — you’ll end up with CSR all over again Using "use client" ❌ Fetching data in client components when it could be server-fetched Fetching data in client components when it could be server-fetched ❌ Passing too much data between RSC and client components via props — instead, let client components be focused, isolated, and stateful Passing too much data between RSC and client components via props ❌ Recreating SSR-style getServerSideProps logic inside RSC — no need, RSC is server-side Recreating SSR-style getServerSideProps is ✅ Decision Tree Summary Here’s a simplified guide: Is it interactive? │ ├── Yes → Client Component (CSR) │ └── No │ ├── Needs per-request data? → SSR │ ├── Can be pre-rendered? → SSG │ └── Otherwise → RSC Is it interactive? │ ├── Yes → Client Component (CSR) │ └── No │ ├── Needs per-request data? → SSR │ ├── Can be pre-rendered? → SSG │ └── Otherwise → RSC You don’t need to memorize it. Once you internalize how rendering maps to responsibility, the decisions become intuitive. the decisions become intuitive The best practice isn’t about picking “the best rendering strategy.” It’s aboutdesigning rendering as an intentional part of your component architecture — with clarity, purpose, and performance in mind. designing rendering as an intentional part of your component architecture 6. Looking Ahead: Why RSC Is More Than Just a Feature 6. Looking Ahead: Why RSC Is More Than Just a Feature React Server Components are not just a performance optimization or a DX enhancement — they represent a foundational shift in how we build React applications. Much like React Hooks in 2019, RSC in 2025 is redefining the baseline for frontend architecture. they represent a foundational shift in how we build React applications redefining the baseline for frontend architecture 🧠 RSC Changes the Mental Model of Building in React Traditional React development was always built on this assumption: “The browser owns the runtime. We hydrate everything. Every piece of logic and data must live in the client, or be fetched via API.” “The browser owns the runtime. We hydrate everything. Every piece of logic and data must live in the client, or be fetched via API.” RSC breaks that assumption. With RSC, you now ask: Can I skip hydration entirely? Can this component run purely on the server? Can I colocate backend logic with my UI? Can I skip hydration entirely? Can this component run purely on the server? Can I colocate backend logic with my UI? It gives us back the ability to separate display logic and interactivity cleanly, not with wrappers and workarounds, but with first-class architectural boundaries. the ability to separate display logic and interactivity cleanly first-class architectural boundaries It’s no longer “client-first.” It’s “purpose-first.” “purpose-first.” Each part of your UI exists where it’s most efficient — server, client, or static. 🌐 Ecosystem Shift Toward Server-First Rendering RSC isn’t happening in isolation. The broader frontend ecosystem is undergoing a server-first rendering renaissance. server-first rendering renaissance Frameworks like: Remix lean heavily into server data loading and form actions. Astro embraces zero-JS by default, shipping only islands of interactivity. Qwik takes hydration to the extreme — deferring all JS until explicitly needed. Next.js 15, with RSC and App Router, now puts per-component rendering at the center of the developer experience. Remix lean heavily into server data loading and form actions. Remix Astro embraces zero-JS by default, shipping only islands of interactivity. Astro Qwik takes hydration to the extreme — deferring all JS until explicitly needed. Qwik Next.js 15, with RSC and App Router, now puts per-component rendering at the center of the developer experience. Next.js 15 per-component rendering at the center This isn’t a coincidence. It’s a reflection of a hard truth we’ve all felt: Sending less JavaScript is the only way to scale interactivity and performance on the modern web. Sending less JavaScript is the only way to scale interactivity and performance on the modern web. React Server Components are the React-native answer to that challenge — deeply integrated, ergonomic, and production-ready. 🔮 What to Expect Next The evolution is still ongoing. As React 19 and the ecosystem mature, we can expect: More granular debugging and profiling tools for RSC trees Better DevTools integration to show boundaries and hydration timelines Higher-order patterns to abstract rendering strategy (e.g., <ServerOnly>, <DeferredClient> wrappers) Broader adoption in design systems, frameworks, and libraries (e.g., RSC-aware UI kits) More granular debugging and profiling tools for RSC trees debugging and profiling tools Better DevTools integration to show boundaries and hydration timelines Better DevTools integration Higher-order patterns to abstract rendering strategy (e.g., <ServerOnly>, <DeferredClient> wrappers) Higher-order patterns <ServerOnly> <DeferredClient> Broader adoption in design systems, frameworks, and libraries (e.g., RSC-aware UI kits) 💬 Enjoyed the read? If this article helped you think differently about React and Next.js 👉 Follow me on HackerNoon for more deep dives Follow me on HackerNoon HackerNoon 👉 Or connect with me on LinkedIn to chat about React, architecture, or RSC migration Or connect with me on LinkedIn LinkedIn
