Resolver v3.0 and GS1 Digital Link Compression (from v3.0 beta 3)

[nicklansley]

Compressing GS1 Digital Link URLs

Resolver CE v3.0 (from beta 3) now supports compressed GS1 Digital Link URLs - and you can use Resolver to find out the compressed version of an uncompressed GS1 Digital Link URL.

A new API call retrieves the compressed version of a GS1 Digital Link URL. Unlike other API requests, this is not part of
the /api endpoint but rather a direct call to the resolving frontend with a query string compress=true.

Request Example:

https://example.com/01/05392000229648/10/LOT01/21/SERIAL01?compress=true

Response:

{
  "response_status": 200,
  "COMPRESSED_LINK": "/AQnO2IRCICDKWcnpqQtCQiJABemo"
}

You can then use this new link by appending it to the domain name:
https://servername.com/AQnO2IRCICDKWcnpqQtCQiJABemo

Let's compare the two lengths:

https://example.com/01/05392000229648/10/LOT01/21/SERIAL01
https://example.com/AQnO2IRCICDKWcnpqQtCQiJABemo

The compression used here is a non-lossy, specialist algorithm conforming to the GS1 Digital Link standard. It has variable success in reducing the length of URLs containing identifiers (and qualifiers).

Implementation Details:

• The Resolver utilise an internal library called the GS1 Digital Link toolkit to detect and decompress inbound requests using this compressed format.
• This compression method uses a combination of uppercase and lowercase characters as well as numbers.

QR Code Storage Considerations

While compressing URLs can simplify their representation, it may not always yield a shorter string suitable for QR Code storage. This is because QR Codes use Unicode characters as storage, which assign varying numbers of digital bits to distinctive character types:

• Numeric characters (0-9) use the fewest bits per character.
• Uppercase characters (A-Z) use more bits than numeric characters.
• Lowercase characters (a-z) use even more bits per character than uppercase characters.

As a result, it's possible that a QR Code with a shorter compressed GS1 Digital Link URL could actually require more storage bits than a numeric-only GS1 Digital Link URL. This increased bit count can lead to a more complex QR Code pattern, which in turn may need to be printed:

• Larger (I look forward to hearing of your discussions with your product packaging design team when you ask for more 'real estate'. Actually, I'll probably hear their reactions from where I live!).
• With finer quality (e.g., higher resolution) which may mean more expensive printers and slowing down the production print run.

To mitigate this effect, try experimenting with different formatting options. For example, see how much simpler a QR Code is when you use uppercase characters for the domain of the URL: HTTPS://EXAMPLE.COM. This should still work and provide valuable insights into optimising your QR Code design.