Vlad Khononov

There is no sense in talking about the solution before we agree on the problem, and no sense talking about the implementation steps before we agree on the solution.

To design and build an effective solution, you have to understand the problem. The problem, in our context, is the software system we have to build. To understand the problem, you have to understand the context within which it exists—the organization’s business strategy, and what value it seeks to gain by building the software.

What Is a Business Domain?
A business domain defines a company’s main area of activity. Generally speaking, it’s the service the company provides to its clients.

To achieve its business domain’s goals and targets, a company has to operate in multiple subdomains. A subdomain is a fine-grained area of business activity. All of a company’s subdomains form its business domain: the service it provides to its customers.

Domain-driven design distinguishes between three types of subdomains: core, generic, and supporting.

A core subdomain is what a company does differently from its competitors. This may involve inventing new products or services or reducing costs by optimizing existing processes.

As the name suggests, supporting subdomains support the company’s business. However, contrary to core subdomains, supporting subdomains do not provide any competitive advantage.

Only core subdomains provide a competitive advantage to a company. Core subdomains are the company’s strategy for differentiating itself from its competitors.

On the contrary, strategically the company would prefer its supporting subdomains to be generic, ready-made solutions, thus eliminating the need to design and build their implementation.

The more complex the problems a company is able to tackle, the more business value it can provide. The complex problems are not limited to delivering services to consumers. A complex problem can be, for example, making the business more optimized and efficient.