Framework guide

Dynamic Open Graph images for SvelteKit

Use a link tag or SvelteKit `handle` to emit `og:image` pointing to your generated OG URL.

Every framework only needs a stable, absolute HTTPS og:image. OGKit gives you one URL, production templates, and query parameters for titles, images, logos, authors, products, events, jobs, and code snippets.

Server-rendered metadata is the SEO boundary

Open Graph images only help distribution when the final HTML response already contains the metadata. Most scrapers do not wait for client-side JavaScript, so React hydration, client routers, and analytics callbacks are too late. Build the OGKit URL in the server route, loader, layout, view helper, or static generation step that owns the document head.

Use one deterministic image URL per canonical page

The strongest pattern is one stable 1200x630 image URL for each canonical URL. Put the same image in Open Graph and Twitter/X metadata, keep the title aligned with the visible H1, and include page-specific context such as author, product name, release version, or docs section. That gives Slack, Discord, LinkedIn, iMessage, and browser-assisted LLM crawlers the same topic signal as the page body.

When to choose hosted templates over custom renderers

Custom Satori, Puppeteer, or screenshot routes make sense when you need arbitrary layout control. Hosted templates make more sense when the business need is repeatable: blog cards, launch pages, changelogs, docs pages, product pages, and comparison pages that should look consistent without a renderer living in every codebase.

Implementation pattern

Generate the OGKit URL before the crawler sees the HTML. That can happen during static generation, in a server route, or in the framework metadata layer. Start with the API reference, deep guides, test the URL in the Playground, then validate the deployed page with the preview debugging tools.

// +page.server.ts
import type { PageServerLoad } from './$types';
export const load: PageServerLoad = async ({ params }) => {
  const title = "Ship notes"; // from CMS/db
  const image = new URL("https://www.webmorp.art/api/og/article");
  image.searchParams.set("key", process.env.OGKIT_KEY!);
  image.searchParams.set("title", title);
  return { title, ogImageUrl: image.toString() };
};

// +page.svelte
<svelte:head>
  <meta property="og:image" content={data.ogImageUrl} />
  <meta name="twitter:card" content="summary_large_image" />
  <meta name="twitter:image" content={data.ogImageUrl} />
</svelte:head>

Deeper SvelteKit notes

Server load is mandatory

SvelteKit crawlers see prerendered or SSR HTML. Build the OGKit URL in server load functions and pass a string into the page. Client-only stores will not fix Slack previews.

Prerendered blogs

For prerender: true routes, the URL is baked at build time — perfect for changelogs and docs. Re-build when titles change, or switch those routes to SSR.

Worked steps

Load title in +page.server.ts.
Build OGKit URL with private env key.
Emit tags in svelte:head.
curl the HTML and confirm absolute og:image.

Checklist

Create ogImageUrl in +page.server.ts / +layout.server.ts.
Pass final URLs into <svelte:head>.
Use absolute production origins.
Keep OGKIT_KEY in private env ($env/static/private).

Common pitfalls

Computing metadata only in the browser
Missing canonical titles
Sharing one card across all routes
Importing secrets into client modules

When a hosted OG API makes sense

A hosted Open Graph image API is useful when you need consistent cards across many pages but do not want to maintain a custom renderer in every app. It is especially useful for docs, changelogs, launch pages, public customer pages, and content collections where the title and summary change often. For HMAC signing and rescrape workflows, see signed URLs and caching & rescrape.

Frequently asked questions

How do I add dynamic Open Graph images to SvelteKit?

Build an absolute OGKit image URL on the server or during static generation, then place it in og:image and twitter:image metadata for each important page.

Can I use OGKit with SvelteKit without a custom image route?

Yes. OGKit returns a normal 1200x630 PNG URL from template and query parameters, so you do not need to maintain a Satori, Puppeteer, or screenshot pipeline.

Where should I keep the OGKit API key?

Keep the API key in server-side environment variables, framework runtime config, or build-time secrets. Do not bundle it into client-side JavaScript.

I changed the title but Slack still shows the old card — what now?

Rebuild/redeploy so HTML has the new OGKit query, confirm with curl, then rescrape Facebook/LinkedIn. Slack often needs a new image URL (updated fields or v=). See /guides/troubleshooting.