Sveltejs Academy · Lesson

Dynamic Route Parameters: [id]

Capture URL segments as parameters using bracket notation in folder names.

Lesson 2 of 413 steps

Dynamic Route Parameters: [id] is a free Sveltejs Academy lesson on CoddyKit. This is lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Sveltejs Academy learning path, and your progress syncs across the web and the CoddyKit app. The Sveltejs Academy course includes 4 lessons in total.

Bracket Folder Names

Use square brackets in folder names for dynamic segments.

src/routes/blog/[slug]/+page.svelte  -> /blog/:slug

Accessing the Parameter

Inside the page, use the $page store from $app/stores.

import { page } from "$app/stores";
<p>Slug: {$page.params.slug}</p>

Load Function Access

Inside +page.js load, use params.slug directly.

export function load({ params }) { return { slug: params.slug }; }

Multiple Params

Use multiple brackets for multi-segment paths.

src/routes/[lang]/[slug]/+page.svelte

Validating Params

Return a 404 from load if the param is invalid.

if (!isValid(params.slug)) error(404, "Not found");

Matchers

Add a src/params matcher to enforce a regex on a parameter.

src/routes/blog/[slug=alpha]/+page.svelte

Defining a Matcher

Create src/params/alpha.js exporting a function.

export function match(value) { return /^[a-z]+$/.test(value); }

SEO with Slugs

Slugs are usually URL-safe IDs. Generate slugs from titles for clean URLs.

Combining Static and Dynamic

Have static folders alongside dynamic ones; static wins on conflict.

Type Safety

SvelteKit generates types for params per route, accessible in the load function arg.

Pre-Rendering Dynamic Routes

Use entries in +page.js to enumerate values to prerender.

Quick Check

How are dynamic segments declared?

Answer it in the interactive lesson

Recap

Use [param] folders for dynamic segments. Access via params in load or $page.params.

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Frequently Asked Questions

Is the “Dynamic Route Parameters: [id]” lesson free?

Yes — the full text of “Dynamic Route Parameters: [id]” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Sveltejs Academy course, upgrade to CoddyKit PRO. The Sveltejs Academy course includes 4 lessons in total.

What will I learn in “Dynamic Route Parameters: [id]”?

Capture URL segments as parameters using bracket notation in folder names. You practise Sveltejs Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Sveltejs Academy?

No prior experience is required. Sveltejs Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 2 of 4.

How long does the “Dynamic Route Parameters: [id]” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Sveltejs Academy lesson?

Yes. Every Sveltejs Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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