Does use of QR Codes powered by GS1 require the use of a resolver?

No.

However, we do very strongly recommend that, one way or another, the GS1 Digital Link URI in the 2D barcode redirects to one or more sources of information about the identified entity. Using a resolver is one way.

For more information, see 

• Connecting barcodes to related information, and
• Redirection: from scan to content.