Is there an article or guide on how banking applications are built?

Question

Backend

Is there an article or guide on how banking applications are built?
I became interested in how a regular banking backend works and what technologies banks use

Answer 1

how does a regular banking backend work and what technologies do banks use

Exactly the same as for ordinary applications (if we exclude very old banks, where the core can spin on very old mainframes)
Just because of the requirements for accessibility, correctness, and security, appropriate practices follow.