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Server-side Image generation with Node.js

Is it possible to generate images from polotno JSON on the backend?

Yes. There is polotno-node package for such a use case.

Using polotno-node you can use most of Polotno Store API. The common usage is image export from Polotno JSON:

const fs = require('fs');
// import polotno-node API
const { createInstance } = require('polotno-node');

async function run() {
// create working instance
const instance = await createInstance({
// to create your own API key please go here:
key: 'nFA5H9elEytDyPyvKL7T',

// load sample json
const json = JSON.parse(fs.readFileSync('polotno.json'));
// here you can manipulate JSON somehow manually
// for example replace some images or change text

// then we can convert json into image
const imageBase64 = await instance.jsonToImageBase64(json); // by default it will be png image
// write image into local file
fs.writeFileSync('out.png', imageBase64, 'base64');

// also we can export design into lower size
// and change image type
const jpegImage = await instance.jsonToImageBase64(json, {
pixelRatio: 0.5, // make image twice smaller
mimeType: 'image/jpeg',
fs.writeFileSync('out.jpg', jpegImage, 'base64');

// close instance