Aug 21, 2026

Converting SVG to PNG is usually the domain of packages such as Sharp. This creates a binary dependency which complicates deployment (develop on Mac, deploy on Linux). The resvg package gives you this functionality without the binary dependency thanks to the included WASM module.

const fs = require( 'fs' );
const path = require( 'path' );

const { Resvg, initWasm } = require( '@resvg/resvg-wasm' );

let wasmReady = false;

async function main( params ) {
  const svg = `
    <svg
      width="640"
      height="480"
      viewBox="0 0 640 480"
      xmlns="http://www.w3.org/2000/svg">
      <style>
        rect {
          fill: ${params.backgroundColor ?? 'red'};
          stroke: none;
        }
      </style>
      <rect
        x="270"
        y="190"
        width="100"
        height="100"
        rx="13"
        ry="13" />
    </svg>
  `;

  if( !wasmReady ) {
    wasmReady = await initWasm( fs.readFileSync( 
      path.join( __dirname, 'index_bg.wasm' ) 
    ) );
  }

  await wasmReady;

  const resvg = new Resvg( svg );
  
  return {
    statusCode: 200,
    headers: {
      'Content-Type': 'image/png'
    },
    body: Buffer.from( resvg.render().asPng() )
  };
}