paper.js/examples/Node.js/SVGExport.js

var paper = require('paper'),
	path = require('path'),
	fs = require('fs');

paper.setup(new paper.Canvas(300, 600));
with (paper) {
	var stops = [new Color(1, 1, 0, 0), 'red', 'black'];

	var radius = view.bounds.width * 0.4,
		from = new Point(view.center.x),
		to = from.add(radius, 0);

	var circle = new Path.Circle({
		center: from,
		radius: radius,
		fillColor: {
			stops: stops,
			radial: true,
			origin: from,
			destination: to
		},
		strokeColor: 'black'
	});

	var from = view.bounds.leftCenter,
		to = view.bounds.bottomRight;

	var rect = new Path.Rectangle({
		from: from,
		to: to,
		fillColor: {
			stops: stops,
			radial: false,
			origin: from,
			destination: to
		},
		strokeColor: 'black'
	});

	rect.rotate(45).scale(0.7);

	var svg = project.exportSVG({ asString: true });
	console.log(svg);

	fs.writeFile(path.resolve(__dirname, 'out.svg'),svg, function (err) {
		if (err) throw err;
		console.log('Saved!');
	});
}