CASE STUDY / Payments & security
Payment protection
Designed payment rate limiting to stop card-testing attacks across approximately six client websites.
MY CONTRIBUTIONIndependent design and implementation
PAYMENT PROTECTION
2 daysImplementation time
Problem
Client e-commerce websites were facing card-testing attacks. The solution needed to block repeated payment attempts without exposing the security rules to attackers.
My contribution
- Designed and implemented two layers of payment rate limiting using C#, ASP.NET, REST APIs, SQL, multithreading, and in-memory caching.
- Added masked API logging and support notifications to make security activity visible without exposing sensitive information.
- Used generic frontend errors to avoid revealing how the blocking logic worked.
Result
Implemented within two days across approximately six client e-commerce websites. Verified that the attacks stopped soon after deployment.