# Build a Single-Page Application in Svelte with svelte-spa-router Single-page applications have become the standard for modern web development, offering users smooth, app-like experiences without full page reloads. Svelte's compilation approach makes it particularly well-suited for SPAs, producing highly optimized JavaScript that updates the DOM efficiently without a virtual DOM overhead. When combined with svelte-spa-router, developers have a lightweight yet powerful routing solution that gives fine-grained control over application navigation. svelte-spa-router is a dedicated client-side routing library designed specifically for building SPAs with Svelte. Unlike SvelteKit's built-in routing system, which provides a full application framework with file-based conventions and server-side rendering capabilities, svelte-spa-router focuses purely on client-side routing for applications that don't need SSR. This makes it an excellent choice for dashboard applications, internal tools, or any project where you're migrating incrementally to Svelte while maintaining a JavaScript-heavy architecture. For teams building [custom web applications](/services/web-development/) that prioritize performance and user experience, choosing the right routing architecture is crucial. Our [frontend development experts](/services/web-development/) can help you evaluate the best approach for your specific requirements. In this guide, you'll learn how to set up routing in your Svelte SPA, configure dynamic routes with parameters, implement authentication guards, and structure your application for maintainability at scale. Whether you're building a simple product showcase or a complex enterprise application, understanding svelte-spa-router gives you a powerful tool for creating seamless single-page experiences.

## What is svelte-spa-router? svelte-spa-router is a lightweight, feature-rich routing library designed specifically for building single-page applications with Svelte. Currently at version 4.0.1 and distributed under the MIT license, the library has become a popular choice for developers who need robust SPA routing without the full SvelteKit framework. It depends on regexparam for route matching, keeping the core implementation focused and maintainable. The library offers a declarative approach to routing where routes are defined as JavaScript objects, making it easy to understand, test, and maintain. Each route maps a URL path to a Svelte component, and the router handles all URL synchronization, history management, and component rendering. This differs fundamentally from SvelteKit's file-based routing, where the directory structure determines your routes. For developers who prefer explicit configuration or are working with existing routing conventions, this object-based approach provides clarity and control. svelte-spa-router supports all essential SPA routing features including route parameters, nested routes, and programmatic navigation while keeping the bundle size minimal. When you need a [custom software solution](/services/custom-software-development/) tailored to your business logic, this level of routing control becomes invaluable. It's an ideal choice when you're building a true SPA without SSR requirements, migrating an existing application incrementally to Svelte, or simply need fine-grained control over routing behavior that file-based conventions don't provide.

## svelte-spa-router vs SvelteKit: Choosing the Right Approach Understanding the differences between svelte-spa-router and SvelteKit's routing system helps you make architectural decisions that align with your project requirements. While both tools handle routing in Svelte applications, they serve different needs and use cases. svelte-spa-router focuses on client-side routing for pure SPAs. It keeps your bundle size minimal at approximately 5KB (gzipped), doesn't include server-side rendering capabilities, and gives you explicit control over route configuration. This makes it ideal for dashboard applications, internal tools, or any project where SEO isn't a primary concern and you want to optimize for load time and runtime performance. SvelteKit, on the other hand, provides a full application framework with file-based routing at its core. Routes are determined by your directory structure, and the framework handles both server-side and client-side rendering. This approach is excellent for content-heavy sites where SEO matters, but it adds complexity and bundle size that may not be necessary for pure SPA applications. For organizations looking to leverage [AI and automation capabilities](/services/ai-automation/) in their web applications, the choice of routing architecture can impact how easily you integrate intelligent features.

1| Feature | svelte-spa-router | SvelteKit |2|---------|-------------------|-----------|3| Bundle Size | Lightweight (~5KB) | Full framework |4| SSR Support | No | Built-in |5| File-based Routing | No | Yes |6| API Routes | No | Yes |7| Learning Curve | Low | Medium-High |8| Best For | True SPAs, incremental migration | SEO-critical, full-stack apps |

## Setting Up Your Svelte SPA Project Before installing svelte-spa-router, you'll need a Svelte project configured with a build tool. Vite has become the standard choice for Svelte projects due to its fast development experience and optimized production builds. If you prefer TypeScript, the Vite Svelte template includes full TypeScript configuration out of the box. To create a new Svelte project with Vite, run the following command in your terminal. This command scaffolds a new Svelte project using the official Vite template with all necessary configurations for development and production builds. This foundation is essential for building professional [web applications](/solutions/web-applications/) that scale. Once your Svelte project is ready, install svelte-spa-router alongside regexparam, which is a required dependency that handles route pattern matching. The installation process is straightforward and the library works immediately without additional configuration.

1# Create new Svelte project2npm create vite@latest my-spa-app -- --template svelte3 4# Navigate to project5cd my-spa-app6 7# Install dependencies8npm install9 10# Install svelte-spa-router11npm install svelte-spa-router regexparam

### Project Structure for a Svelte SPA A well-organized SPA project separates concerns between routing configuration, page components, and shared UI elements. The recommended structure keeps route configuration in a dedicated file, components organized by purpose, and page components in their own directory. This separation improves maintainability as your application grows and makes it easier for team members to understand where to make changes. The `src/routes.js` file contains your route definitions as JavaScript objects, making routes easy to review and modify without touching individual page components. The `src/components/` directory holds reusable UI elements like headers, navigation menus, and footers that appear across multiple pages. The `src/pages/` directory contains the actual page components that render for each route, keeping them separate from shared UI elements.

## Configuring Routes Route configuration in svelte-spa-router follows a simple declarative pattern that maps URL paths to Svelte components. Routes are defined as an array of objects, where each object specifies the path pattern using the `name` property and the component to render using the `component` property. This approach makes route definitions self-documenting and easy to modify. Route order matters because svelte-spa-router uses first-match semantics, meaning the router evaluates routes in order and renders the first matching route. More specific routes should generally appear before general ones, and catch-all routes like 404 pages should appear last. For example, a dynamic route like `/user/:id` should come before a static route like `/users` if both patterns could theoretically match the same URL. Each route object can include additional options for more advanced scenarios, including component props that get passed to the rendered component and conditional rendering logic through wrapper components.

1import Home from './pages/Home.svelte';2import About from './pages/About.svelte';3import Users from './pages/Users.svelte';4import UserDetail from './pages/UserDetail.svelte';5 6const routes = [7    { name: '/', component: Home },8    { name: '/about', component: About },9    { name: '/users', component: Users },10    { name: '/user/:id', component: UserDetail }11];12 13export default routes;

### Dynamic Route Parameters Modern applications often need URLs that include dynamic segments, such as user IDs, product slugs, or category names. svelte-spa-router supports this through route parameters using the familiar colon syntax. Parameters captured from the URL are automatically parsed and made available to your components through the page store. For example, a route defined as `/user/:id` matches URLs like `/user/123` or `/user/john-doe`, extracting the dynamic segment as the `id` parameter. Multiple parameters are supported in a single route using patterns like `/posts/:category/:slug`, allowing you to capture multiple segments from the URL path. To access these parameters in your component, you subscribe to the `page` store from the router and use reactive statements to extract parameter values. The page store contains the current route information including params, location, and route name, all of which update automatically when the URL changes. Consider adding validation for captured parameters in your components, especially when parameters represent IDs or other values used in database queries.

1<script>2    import { page } from 'svelte-spa-router';3 4    $: userId = $page.params.id;5</script>6 7<h1>User Profile: {userId}</h1>

## Building the Router Component The Router component is the foundation of navigation in your SPA. It wraps your application content and handles all the complexity of URL changes, route matching, and component rendering. In svelte-spa-router, the Router is typically placed at the root of your application in the main App component. To set up the router, import the Router component and your route configuration, then pass your routes array as a prop. Any content nested inside the Router component will be replaced by the matched route's component based on the current URL. This means you typically want to wrap your entire application content or at least the section where routed content should appear. For applications that need persistent navigation elements like headers or sidebars, place those elements outside the Router component so they remain visible across all routes. The Router only controls what it directly wraps, giving you flexibility in how you structure your component hierarchy for different layout requirements.

1<script>2    import Router from 'svelte-spa-router';3    import routes from './routes.js';4</script>5 6<Router {routes}>7    <App />8</Router>

## Navigation and Links Effective navigation is crucial for SPA user experience. svelte-spa-router provides a Link component that creates navigation links that update the URL without triggering full page reloads. This component should be used instead of standard `<a>` tags for in-app navigation because it intercepts clicks and uses the router's navigation API, maintaining the SPA experience. The Link component works similarly to an anchor tag but provides additional features specific to SPA navigation. The `href` prop specifies the destination route, and the component automatically highlights itself when the current route matches. You can customize this active state styling through the `activeClass` prop, which applies a CSS class when the link is active. Additional Link props include `disabled` for preventing navigation while keeping the link visible, `replace` to replace the current history entry instead of pushing a new one (useful for redirect scenarios), and custom event handlers for advanced scenarios like tracking navigation events or showing confirmations before navigation.

1<script>2    import { Link } from 'svelte-spa-router';3</script>4 5<nav>6    <Link href="/">Home</Link>7    <Link href="/about">About</Link>8    <Link href="/users">Users</Link>9</nav>

### Programmatic Navigation Sometimes you need to navigate based on events other than link clicks, such as form submissions, button clicks, or API callbacks. The router's `push` method enables programmatic navigation by adding a new entry to the browser's history stack. This is commonly used after successful form submissions, authentication events, or any action that should transition the user to a new view. The `replace` function provides an alternative for navigation that shouldn't create a new history entry. This is useful for redirects after authentication, where you don't want users to be able to navigate back to a login form using the browser's back button. Understanding when to use push versus replace helps you create navigation flows that match user expectations. Conditional navigation patterns are common in real applications, where you might navigate based on user roles, form validation results, or API responses. Both push and replace accept URL paths with query parameters, allowing you to pass additional context to the destination route when needed.

1import { push } from 'svelte-spa-router';2 3function handleLogin() {4    // Perform authentication...5    push('/dashboard');6}7 8function handleError() {9    push('/error?message=Authentication failed');10}

1import { replace } from 'svelte-spa-router';2 3// After successful logout, replace to prevent going back4replace('/login');

## Nested Routes and Layouts Complex applications often need hierarchical navigation where certain sections have their own sub-navigation structure. svelte-spa-router handles this through component composition rather than a nested router concept, giving you flexibility in implementation while keeping the routing logic simple. A common pattern uses a layout component that renders both the sub-navigation and an outlet for child routes. The layout component uses Svelte's slot system to render child route content, keeping the layout logic with the layout component while allowing child routes to focus on their specific functionality. To implement nested routes, define them in your routes array with the parent layout component and child routes that expect the layout to be present. When the parent route matches, the layout component renders, and subsequent URL changes within that context render different child components in the slot. This pattern works well for admin dashboards, settings sections, or any area of your application with its own navigation structure.

1<!-- AdminLayout.svelte -->2<script>3    import { Link } from 'svelte-spa-router';4</script>5 6<div class="admin-layout">7    <aside class="admin-nav">8        <Link href="/admin/dashboard">Dashboard</Link>9        <Link href="/admin/users">Users</Link>10        <Link href="/admin/settings">Settings</Link>11    </aside>12 13    <main class="admin-content">14        <slot />15    </main>16</div>

1const routes = [2    { name: '/admin', component: AdminLayout },3    { name: '/admin/dashboard', component: Dashboard },4    { name: '/admin/users', component: UserList },5    { name: '/admin/settings', component: Settings }6];

## Route Guards and Authentication Many applications need to protect certain routes from unauthorized access. While svelte-spa-router doesn't have built-in route guards like some frameworks, you can implement authentication and authorization through wrapper components that wrap your protected content. A wrapper component approach keeps authentication logic reusable across protected routes. The wrapper checks authentication state before rendering the protected component, redirecting unauthenticated users to a login page using the push function. This pattern can be extended to handle role-based authorization, permission checking, or any other pre-render validation. When using wrapper components for route protection, you pass the actual component to render as a prop, and the wrapper conditionally renders it based on authentication state. This keeps your route definitions clean while centralizing authentication logic in a reusable component. For applications with many protected routes, consider creating a helper function or higher-order component that wraps routes with protection logic.

1<!-- ProtectedRoute.svelte -->2<script>3    import { push } from 'svelte-spa-router';4    import { isAuthenticated } from './auth.js';5 6    export let component;7    export let redirectTo = '/login';8 9    $: if (!$isAuthenticated) {10        push(redirectTo);11    }12</script>13 14{#if $isAuthenticated}15    <svelte:component this={component} />16{/if}

1const routes = [2    {3        name: '/dashboard',4        component: ProtectedRoute,5        props: { component: Dashboard }6    }7];

## State Management for Routing SPAs often need to share route-related state across components, such as the current path, query parameters, or matched route data. svelte-spa-router provides stores that expose this information in a reactive way, making it easy to build UI that responds to URL changes. The `page` store contains the current route information including params, location, and route name. By subscribing to this store, your components automatically update when the URL changes, enabling reactive UI patterns that reflect the current navigation state. The `querystring` store parses URL query parameters into a string that you can process with URLSearchParams. Common patterns for route-driven UI include showing or hiding navigation elements based on the current route, highlighting active menu items, reading query parameters for filtering or search functionality, and conditionally rendering content based on route parameters. These patterns help create seamless user experiences where the UI responds naturally to navigation without requiring full page reloads.

1<script>2    import { page, querystring } from 'svelte-spa-router';3 4    $: currentPath = $page.location.pathname;5    $: currentParams = $page.params;6    $: searchParams = new URLSearchParams($querystring);7    $: searchTerm = searchParams.get('q') || '';8</script>9 10<nav class:hidden={$page.location.pathname === '/login'}>11    <!-- Navigation visible except on login page -->12</nav>

## Best Practices for Svelte SPAs Building a successful SPA requires attention to several architectural concerns beyond just routing. Following these best practices helps ensure your application remains maintainable and performant as it grows. For enterprise applications, consider partnering with a [custom software development team](/services/custom-software-development/) that understands SPA architecture patterns. **Route Organization**: Keep route definitions in a dedicated file that can be imported wherever routes are needed. Consider grouping related routes for easier maintenance. A well-organized routes file serves as documentation for your application's URL structure and makes onboarding new team members easier. **Code Splitting**: For larger applications, lazy-loading route components reduces initial bundle size and improves load time. Svelte's dynamic imports work seamlessly with route components, allowing you to load pages only when they're needed. This is particularly valuable for admin sections, less frequently accessed pages, or any area of your application with heavy dependencies. **Error Handling**: Implement a catch-all route for 404 pages that renders when no other routes match. This ensures users who navigate to invalid URLs see a helpful message rather than a broken experience. The catch-all route should use a pattern that matches any remaining URL, placed last in your route configuration. **Accessibility**: Ensure all navigation uses proper ARIA attributes and keyboard support. The Link component handles most accessibility concerns, but custom navigation patterns should follow WCAG guidelines. Test your navigation with keyboard-only navigation to ensure all interactive elements are accessible.

1const routes = [2    { 3        name: '/dashboard', 4        component: async () => (await import('./pages/Dashboard.svelte')).default 5    }6];

1const routes = [2    // ... other routes3    { name: '/(.*)', component: NotFound }4];

## When to Use svelte-spa-router vs SvelteKit Understanding when to choose each approach helps you avoid architectural mismatches that could complicate your project later. svelte-spa-router excels for pure SPA applications where client-side rendering is sufficient, while SvelteKit provides additional capabilities for content-focused sites. For [web application development](/solutions/web-applications/) that requires high interactivity and fast user interactions, choosing the right routing framework is essential. Choose svelte-spa-router when you're building a true SPA without SSR requirements, such as dashboard applications, internal tools, or interactive web applications where users are authenticated. It's also an excellent choice when migrating an existing application to Svelte incrementally, as it works alongside your current architecture without requiring a full rewrite. If you need fine-grained control over routing behavior or want to minimize bundle size for faster load times, svelte-spa-router is the right choice. Choose SvelteKit when SEO matters and server-side rendering is required for content indexing. SvelteKit's file-based routing conventions provide a productive workflow for content-focused sites, and built-in features like image optimization and API routes make it a full-stack solution. If you're building a marketing site, blog, or any application where organic search traffic is important, SvelteKit is the more appropriate choice despite its larger footprint. For complex projects that may benefit from [intelligent automation and AI integration](/services/ai-automation/), consider how your routing architecture will support future feature additions.

1| Choose svelte-spa-router when... | Choose SvelteKit when... |2|--------------------------------|---------------------------|3| Building a true SPA without SSR | SEO matters and SSR is required |4| Migrating incrementally to Svelte | Need built-in image optimization |5| Needing fine-grained routing control | Prefer file-based routing conventions |6| Prioritizing minimal bundle size | Want server-side data loading patterns |7| No server-side rendering needed | Need API routes and server endpoints |