# 21 QR Reference (QRR)

## Validate a QR reference

 - [POST /v2/qr-reference/validate](https://apis.codeblock.ch/qr-invoice/api-docs/21-qr-reference-(qrr)/validate_2.md)

## Normalize a QR reference

 - [POST /v2/qr-reference/normalize](https://apis.codeblock.ch/qr-invoice/api-docs/21-qr-reference-(qrr)/normalize.md)

## Calculate Check Digit by Modulo 10 recursive

 - [POST /v2/qr-reference/modulo10recursive](https://apis.codeblock.ch/qr-invoice/api-docs/21-qr-reference-(qrr)/modulo10recursive.md)

## Format a QR reference

 - [POST /v2/qr-reference/format](https://apis.codeblock.ch/qr-invoice/api-docs/21-qr-reference-(qrr)/format.md)

## Extract the actual reference number from a QR Reference

 - [POST /v2/qr-reference/extract](https://apis.codeblock.ch/qr-invoice/api-docs/21-qr-reference-(qrr)/extract.md)

## Create a QR reference with an optional customer ID. If the passed QR reference is missing checksum, it is calculated and appended.

 - [POST /v2/qr-reference/create](https://apis.codeblock.ch/qr-invoice/api-docs/21-qr-reference-(qrr)/create_2.md)