One contactless payment in London, every message it sends, and where the money moves
Pick a route and step through the journey. Each step shows who talks to whom, the call or message they send, a payload built from the documented field names, and what is different from a bank card in a phone wallet.
card-network messagewallet request or fundingthe active stepnot confirmed
ISO 8583 field numbers and every amount, identifier and rate are illustrative. The GBP to KRW rate is a placeholder, not a quote. Dashed hops are not confirmed in the public documentation.
Vishwanath Callikan, MBA
Source: Alipay+ NFC developer documentation (product introduction, SDK overview, integration overview, make a payment, "Convert authorization to pay", cancel a payment), Alipay+ MPP transaction detail report, Alipay+ acquirer FAQ, Kakao Pay overseas-payment help, Alipay and Mastercard release on Kakao Pay of 22 Sep 2025, Mastercard Wallet Pay release of 10 Sep 2026, Verestro MDES and MCBP developer notes.