Structure of modern electronic financial/payment systems

Question

Payment systems

Are there any resources on the inner workings of financial systems?

Interested in a wide range of issues, both on the tools used and on possible tricks.
Something like insign.ru for highload...

Answer 1

Financial systems is the most conservative segment of the market. Having worked in it, I realized that often the technologies and techniques (!) of a decade ago are considered modern in it. Therefore, if you find articles that are five years old, you are very likely to get up-to-date information.
The newest and most modern technologies are usually used by new players. This allows them to quickly get ahead and gain momentum (And fall just as quickly if you don’t think about patching holes in time).
Most of the new players in the financial sector are instant money payments, forex and electronic money. I don't know much about them, so I won't lie. However, the main Highload is concentrated here, since such small payments are most in demand among the population.
More old ones are money transfers without opening an account and Internet monitoring of your finances (namely monitoring).
The highload of systems of this type known to me is provided for the most part by the capabilities of the DBMS and horizontal scaling. In other words, we work via HTTP and distribute the load across application servers. At the same time, we leave as much as possible for the execution of the scheduler on a separate server.
In addition to plain HTTP+XML, the most "modern" samples use SOAP.
The oldest representatives of the sector are Remote Banking (and Internet banking in particular).
Here you can meet real dinosaurs: self-written procedural languages, naked JavaScript without frameworks, visual forms made on Delphi 5. Frankly, I would not call these systems even close to Highload, since 2-3 thousand simultaneously connected clients can significantly hang the system (if not kill). Actually, for this reason, Internet banking and remote banking services in particular are still not very widespread.
Such a significant lag in technology is associated with great risks when using new products. If the site is broken, then it will lose part of the profit if the bank is broken ...
Although it is worth noting that there are solutions written in Java and C # on this market, however, their share is still very small and the rating is extremely low due to the small functionality.
Internet banking rating
In addition, it is worth noting the class of systems called "card processing". They ensure the functioning of payments and blocking funds on plastic cards. And Highload is extremely necessary there, but the area is extremely narrow and, as a rule, processing does not work directly with the client, but receives verified and processed information from the bank. Card processing known to me is written in C++.
Unfortunately, I do not know where (except my own head) to get such information about the architecture of banking systems, but I hope I managed to give a superficial idea of ​​\u200b\u200bwhat it looks like from the inside and show search directions.