og-img

This is a framework agnostic package for generating Open Graph images using Satori and resvg. Built using Web APIs, this package can be executed with Node.js and on the edge. You can use this package to add dynamic Open Graph images to your SvelteKit, Astro, SolidStart or Qwik website.

The difference to @vercel/og is that this package loads the WebAssembly module needed to convert SVG to PNG lazily at runtime and provides a framework agnostic workaround for defining the content of the images using satori-html.

Installation

This library is available for Node and Bun.

npm install og-img    # npm
yarn add og-img       # yarn
pnpm add og-img       # pnpm
bun add og-img        # bun

How it works

To generate an image, all you need to do is return an ImageResponse via a server endpoint. You can use html to easily define the content of your image.

To get proper syntax highlighting for the tagged template literal in Visual Studio Code, you can install the lit-html extension.

import { ImageResponse, html } from 'og-img';

async function loadFont(url: string) {
  const resposne = await fetch(url);
  return resposne.arrayBuffer();
}

// With SvelteKit
export async function GET() {
  return new ImageResponse(
    // Use Tailwind CSS or style attribute
    html`
      <div tw="text-4xl text-green-700" style="background-color: tan">
        Hello, world!
      </div>
    `,
    {
      width: 1200,
      height: 600,
      fonts: [
        {
          name: 'Roboto',
          // Use `fs` (Node.js only) or `fetch` to read font file
          data: await loadFont('https://www.example.com/fonts/roboto-400.ttf'),
          weight: 400,
          style: 'normal',
        },
      ],
    }
  );
}

// With Qwik
export const onGet = async ({ send }) => {
  send(
    new ImageResponse(
      // Use Tailwind CSS or style attribute
      html`
        <div tw="text-4xl text-green-700" style="background-color: tan">
          Hello, world!
        </div>
      `,
      {
        width: 1200,
        height: 600,
        fonts: [
          {
            name: 'Roboto',
            // Use `fs` (Node.js only) or `fetch` to read font file
            data: await loadFont(
              'https://www.example.com/fonts/roboto-400.ttf'
            ),
            weight: 400,
            style: 'normal',
          },
        ],
      }
    )
  );
};

Then all you need to do is point to your API endpoint with a meta tag in the head of your website to embed the Open Graph image.

<head>
  <title>Hello, world!</title>
  <meta property="og:image" content="https://www.example.com/og-image" />
</head>

You can use URL parameters to dynamically change the content of your Open Graph image. Take a look at Valibot's Open Graph image. You can find the source code here.

Credits

Satori: https://github.com/vercel/satori
Satori HTML: https://github.com/natemoo-re/satori-html
resvg: https://github.com/RazrFalcon/resvg
resvg-js: https://github.com/yisibl/resvg-js

Feedback

Find a bug or have an idea how to improve the library? Please fill out an issue. Together we can make the library even better!

License