Book “Architecture of Payment Systems”

After many years in Banking and FinTech, I collected a large amount of material about payment systems, architecture approaches, vendors, integrations, regulations and implementation problems.

For a long time, these materials existed mainly as part of my own working knowledge: notes, diagrams, documents, examples from projects, questions I had to answer and decisions I had to make.

My recent engagement as an External CTO of a large forex and crypto-trading platform in the UAE made the problem especially clear. Again, I had to work with many connected areas at the same time: payments, banking integrations, trading, crypto, compliance, vendors, existing systems, business goals and product plans.

At that point I decided that I should stop only collecting material and start turning it into a book.

We live in a world where AI can quickly provide explanations, comparisons and technical information. I use these capabilities too, and I think they are useful.

But architecture of a complex payment platform is not a sequence of independent questions.

To make a good decision, you often need to keep dozens of facts and dependencies in the same context. Business requirements affect the architecture. Architecture affects vendor selection. A vendor affects certification and operations. A regional requirement can change the integration model. An existing product can remove one problem and create another.

AI can help us work with information. My goal for this book is to provide a structure for that information: fundamentals, relationships, decision points and practical questions that help us reason about the system as a whole.

I am still classifying the materials I collected over the years. The structure below is therefore a working map.

Some topics will probably move. Some may grow. Some may eventually become separate books. I prefer to let the structure follow the material instead of forcing everything into the first version of a table of contents.

It is easy to describe architecture at a level where every component is only a box on a diagram.

Real projects do not work like that. At some point we need to decide whether a real product can provide the required capability, how it integrates with our platform, what it owns, what it exposes and what limitations come with it.

For this reason, I plan to use real vendors and solutions throughout the book where they help explain an architecture choice.

At the same time, the vendor itself should not become the lesson. Vendors change. Products change. Companies merge. APIs are replaced. Features appear and disappear.

The useful part is understanding why a product fits one architecture, why another product fits a different one and which questions should be asked before making the choice.

I want the process of writing this book to be open enough that useful feedback can arrive while it can still change the result.

I plan to publish updates about topics I am researching, changes in the structure, selected draft material, questions I am trying to answer and opportunities to review or discuss parts of the book.

If this subject is close to your own work, you can follow the project and join the discussion when you have something to add.

Writing this book requires time for research, classification of materials, preparation of examples, comparison of architecture approaches and review of real products and solutions.

If you find this project useful and would like to support the work financially, you can make a contribution using one of the options below.

Financial support is completely optional. Sending a real question, reviewing a draft, sharing your own experience, discussing the material or simply following the project is already valuable to me.

I would also like to recognise people and organisations that provide meaningful support to the project. The exact form of recognition may evolve together with the book, but I will try to say thank you in a suitable way where it makes sense.