This is the beginning of series on Microservices & Event-Driven Architecture (MEDA). The series explores the theme from its historical context to practical topics like testing, deployment, and observability.

All research and writing are done by me. The ideas are drawn from respected books and lectures, as well as my own professional experience. No AI is used to generate the content itself; I use ChatGPT only for editing, as English is not my native language, and I believe the texts benefit from AI corrections of my grammar and fluency.

I hope you find this series helpful and interesting. If you notice any errors or have suggestions, feel free to contact me at george@mishurovsky.com or leave a comment — I read them all.

Now, let’s proceed to the topic.

It helps to settle with fundamentals before diving into modern software architecture buzzwords like ‘microservices’ and ‘event-driven systems’.

A service is:

• a self-contained unit of functionality
• serving a specific business purpose
• owning both its logic and data
• deployed independently
• providing capabilities through a standardized interface
• accessed through a network boundary (real or assumed)

Note the emphases on autonomy and boundaries (functional and communicational). Without those, we’re talking about components, but not services.

Understanding this distinction makes architectural discussions clearer and prevents “microservices” from becoming just a fancy label for a distributed monolith.