@vercel/og

What is @vercel/og?

@vercel/og is a package designed to generate Open Graph images dynamically. It allows developers to create custom social media preview images on the fly using HTML and CSS, which can be particularly useful for generating unique images for each page or post on a website.

What are @vercel/og's main functionalities?

Generate Open Graph Images

This feature allows you to generate Open Graph images dynamically using HTML and CSS. The code sample demonstrates how to create an image with a custom title passed as a query parameter.

const { ImageResponse } = require('@vercel/og');

export default function handler(req, res) {
  const { searchParams } = new URL(req.url, 'http://localhost');
  const title = searchParams.get('title') || 'Default Title';

  const image = new ImageResponse(
    <div style={{
      fontSize: 128,
      color: 'white',
      background: 'black',
      width: '100%',
      height: '100%',
      display: 'flex',
      alignItems: 'center',
      justifyContent: 'center',
    }}>
      {title}
    </div>,
    {
      width: 1200,
      height: 630,
    }
  );

  res.setHeader('Content-Type', 'image/png');
  res.send(image);
}

Other packages similar to @vercel/og

puppeteer

Puppeteer is a Node library which provides a high-level API to control Chrome or Chromium over the DevTools Protocol. It can be used to generate screenshots and PDFs of web pages, which can include Open Graph images. Compared to @vercel/og, Puppeteer offers more flexibility and control over the browser environment but requires more setup and resources.

html-to-image

html-to-image is a library that allows you to convert HTML nodes to images in various formats. It is simpler and more lightweight compared to @vercel/og, but it may not offer the same level of customization and dynamic content generation capabilities.

sharp

Sharp is a high-performance image processing library for Node.js. It can be used to create, manipulate, and convert images. While it does not directly generate images from HTML/CSS like @vercel/og, it can be used in conjunction with other tools to achieve similar results.

README

Open Graph Image Generation

Generate Open Graph images with Vercel’s Edge Function.

Quick Start

Install @vercel/og, then use it inside an API route with Edge Runtime configured in your Next.js project:

// /pages/api/og.jsx
import { ImageResponse } from '@vercel/og'

export const config = {
  runtime: 'experimental-edge',
}

export default function () {
  return new ImageResponse(
    (
      <div
        style={{
          width: '100%',
          height: '100%',
          display: 'flex',
          alignItems: 'center',
          justifyContent: 'center',
          fontSize: 128,
          background: 'lavender',
        }}
      >
        Hello!
      </div>
    )
  )
}

Then run next dev and access localhost:3000/api/og, the React element will be rendered and responded as a PNG from that endpoint:

Read more about the API, supported features and check out the examples in the following sections.

API Reference

@vercel/og only supports the Edge Runtime. The Node.js runtime will not work.

The package exposes an ImageResponse constructor, with the following options available:

import { ImageResponse } from '@vercel/og'

// ...
new ImageResponse(
  element: ReactElement,
  options: {
    width?: number = 1200
    height?: number = 630
    emoji?: 'twemoji' | 'blobmoji' | 'noto' | 'openmoji' | 'fluent' | 'fluentFlat' = 'twemoji',
    fonts?: {
      name: string,
      data: ArrayBuffer,
      weight: number,
      style: 'normal' | 'italic'
    }[]
    debug?: boolean = false

    // Options that will be passed to the HTTP response
    status?: number = 200
    statusText?: string
    headers?: Record<string, string>
  },
)

When running in production, these headers will be included by @vercel/og:

'content-type': 'image/png',
'cache-control': 'public, immutable, no-transform, max-age=31536000',

During development, the cache-control: no-cache, no-store header is used instead.

Supported HTML and CSS Features

Please refer to Satori’s documentation for a list of supported HTML and CSS features.

By default, @vercel/og only has the Noto Sans font included. If you need to use other fonts, you can pass them in the fonts option. Check the Custom Font example below for more details.

Examples

• Basic · source · demo
• Embed SVG Image · source · demo
• Dynamic PNG Image Based on URL Queries · source · demo
• Fetch External Data · source · demo
• Custom Font · source · demo
• Emoji · source · demo
• Languages · source · demo
• Encrypted Token · source · demo

Development / Contributing

Playground

• pnpm i inside the playground/ directory
• pnpm dev to start the Next.js app

Package

• pnpm i inside the root directory
• pnpm build to build the library
• pnpm types to generate the types

Acknowledgements

This project will not be possible without the following projects:

• Satori
• Twemoji
• Google Fonts and Noto Sans
• Resvg and Resvg.js

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