// This generates a string like: '<svg>...</svg>'
  $svgString = getSvgStringFromSvgFile(session('svgFile'));

  $output = $snappy->getOutputFromHtml($svgString, [
    'encoding' => 'utf-8',
    'title' => session('svgTitle')
  ]);
  $output = base64_encode($output);

  return response()->json($output);

<object data={'data:application/pdf;base64,' + pdfData} type="application/pdf">
          Your browser doesn't support pdf embedding.
        </object>