import 'dart:convert'; import 'dart:typed_data'; String base64UrlNoPadEncode(List bytes) { var x = base64Url.encode(bytes); while (x.endsWith('=')) { x = x.substring(0, x.length - 1); } return x; } Uint8List base64UrlNoPadDecode(String source) { source = base64.normalize(source); return base64.decode(source); }