It’s what a company does differently from its competitors, it’s what gives them the competitive edge - inventing new products/services or reducing costs by optimizing existing processes.
Example:
Google Search’s ranking algorithm. At the time of this writing, Google’s advertising platform accounts for the majority of its profits. That said, Google Ads is not a subdomain, but rather a separate business domain with subdomains comprising it, among its cloud computing service (Google Cloud Platform), productivity and collaboration tools (Google Workspaces), and other fields in which Alphabet, Google’s parent company, operates. But what about Google Search and its ranking algorithm? Although the search engine is not a paid service, it serves as the largest display platform for Google Ads. Its ability to provide excellent search results is what drives traffic, and subsequently, it is an important component of the Ads platform. Serving suboptimal search results due to a bug in the algorithm or a competitor coming up with an even better search service will hurt the ad business’s revenue. So, for Google, the ranking algorithm is a core subdomain.
Features
- Complexity. A core subdomain that is simple to implement can only provide a short-lived competitive advantage.
- Not necessarily technical. The competitive advantage can be in the quality of produced products, their design, or highly trained personnel.
- Highly volatile. The work on core subdomains is never done: new features, optimizing existing functionality. The constant evolution is essential to stay ahead of company’s competitors. Since it’s expected to change often, the code should be maintainable and easy to evolve. Thus, core subdomains require implementation of the most advanced engineering techniques.
- In-house implementation. It’s a strategic investment, and it’s unwise to outsource the implementation of the core subdomain. Most skilled talents of the organization should be assigned to work on it.
We should always aim to keep clear boundaries between core subdomains and everything else. It will allow us to invest time where it matters the most.
How to Identify in the Legacy code (Brownfield project)
- What differentiates company from its competitors?
- Does it have a “Secret sauce” that competitors lack? Intellectual property such as patents, algorithms designed in-house.
- Does it have any nontechnical advantage? The ability to hire top-level personnel, unique artistic design etc.
- The big ball of mud components may help to identify the core subdomain. All engineers hate these, but the business is unwilling to rewrite it because of the business risk at stake.