In this video, I break down the entire credit card transaction flow - from the moment you tap, through Visa's network, to the banks, and back. We're talking milliseconds, multiple parties, and a system processing $13 trillion annually.

We'll cover:
→ The ISO 8583 message format
→ How card networks like Visa actually work  
→ What acquirers and issuers do
→ Real-time authorization flow
→ Why some transactions get declined
→ The rise of programmable cards

This video is sponsored by Klutchcard - a new way to manage subscriptions with virtual cards. Check them out: https://www.klutchcard.com/developer

https://www.linkedin.com/in/bytemonk/

Timestamps
0:00 - What happens when you tap your card
1:12 - Inside the transaction data packet
2:28 - How Visa routes your payment
3:45 - Acquirers & payment processors explained
4:52 - Your bank decides: approve or decline
5:38 - The 2-second return journey
6:24 - Why transactions sometimes fail
7:15 - Programmable cards & virtual numbers
8:32 - Banking-as-a-Service (deep dive coming)

https://www.youtube.com/playlist?list=PLJq-63ZRPdBt423WbyAD1YZO0Ljo1pzvY
https://www.youtube.com/playlist?list=PLJq-63ZRPdBssWTtcUlbngD_O5HaxXu6k
https://www.youtube.com/playlist?list=PLJq-63ZRPdBu38EjXRXzyPat3sYMHbIWU
https://www.youtube.com/playlist?list=PLJq-63ZRPdBuo5zjv9bPNLIks4tfd0Pui
https://www.youtube.com/playlist?list=PLJq-63ZRPdBsPWE24vdpmgeRFMRQyjvvj
https://www.youtube.com/playlist?list=PLJq-63ZRPdBslxJd-ZT12BNBDqGZgFo58

AWS Certification: 
AWS Certified Cloud Practioner: https://youtu.be/wF1pldkQrOY
AWS Certified Solution Architect Associate: https://youtu.be/GzomXNLFgkk
AWS Certified Solution Architect Professional: https://youtu.be/KFZrBxSA9tI

#SystemDesign #CreditCards #Fintech #HowItWorks #Visa #Payments

ByteMonk

Credit card transactions travel through a 50-year-old system that makes approval decisions in ~300 milliseconds using static rules. Programmable credit cards inject a middleware layer into this flow, allowing developers to write custom code that executes during the authorization window. This enables real-time transaction controls like blocking purchases at certain times, setting merchant-specific limits, creating virtual cards with custom rules, and receiving webhooks for instant notifications. The system works by intercepting ISO 8583 payment messages and running custom logic against rich transaction metadata before the bank's decision engine processes the request.

Credit Card Transactions Decoded: From Tap to Bank in 2 Seconds