chs=<width>x<height>Required Image size.
chl=<data>Required The data to encode. Data can be digits (0-9), alphanumeric characters, binary bytes of data, or Kanji. You cannot mix data types within a QR code. The data must be UTF-8 URL-encoded. Note that URLs have a 2K maximum length, so if you want to encode more than 2K bytes (minus the other URL characters), you will have to send your data using POST.
L- [Default] Allows recovery of up to 7% data loss
M- Allows recovery of up to 15% data loss
Q- Allows recovery of up to 25% data loss
H- Allows recovery of up to 30% data loss