Q: Why the Notification URL is Missing for Certain Transactions?
Answer:
The Notification URL is only applicable for transactions processed through the Browser (BRW) device channel.
It is not used for App-based (APP) transactions because the ACS communicates directly with the 3DS SDK during the challenge, so there’s no need for a browser-based callback.
To confirm the device channel of the transaction, you can go to its transaction details page and look for “Device Channel”. You’ll find it in the Transaction Master Details section (the first section of the page).
Q: What is Notification URL?
Answer:
According to EMV® 3-D Secure Protocol and Core Functions Specification v2.3.1.1:
A Fully Qualified URL of the system that receives the CRes message or Error Message. The CRes message is posted by the ACS through the Cardholder Browser at the end of the challenge and after receipt of the RRes message.
In simple terms:
It’s a web address provided by the merchant (in the AReq message) where the ACS sends the final challenge result (CRes) or an error message through the cardholder’s browser. This happens after the ACS has completed its internal steps and received the RRes, at the end of the challenge process.
Q: Why only for Browser flows (BRW) and not App flows (APP)?
Answer:
- In browser-based flows, the ACS cannot directly communicate with the merchant’s backend because the interaction happens through the cardholder’s browser. So, the Notification URL ensures the ACS can deliver the final result back to the merchant through the browser.
- In app-based flows, the ACS communicates directly with the 3DS SDK during the challenge. There’s no browser involved, so a Notification URL is not needed.