A God Class is a class that knows too much or does too much. It is an anti pattern where the intelligence of the system is centralized in a single place (Riel, 1996; Fowler, 1999).
In the early part of my career, I had just resumed as a junior software developer when a senior colleague was leaving the organization. My first assignment was to maintain an application he handed over to me.
The first thing I noticed in one of his main classes was a comment block containing his email and phone number, followed by: "Whatever your experience is using this code, you can contact me."
I laughed at first, but soon realized he wasn't joking.
The entire app depended on one massive God Class that handled everything. To make matters worse, it was a legacy code written in PHP 4, which allowed implicit variable declarations. The result was a codebase filled with hidden variables and unpredictable behaviors. From the outside, the application looked fine. Inside, it was chaos.
Not long after, the client urgently requested a new feature to be delivered within 10 days. Suddenly, that comment with his phone number made perfect sense 😀.
Working with this application made the dangers of God Objects clear:
- Tight coupling: A small change could trigger unexpected issues in unrelated features.
- High complexity: The class did too much that understanding it required reading through hundreds of lines of unrelated logic.
- Poor design: Instead of modeling real-world objects and interactions, everything was dumped into one place.
- Technical debt: It gave the illusion of speed in the short term, but created long-term headaches for anyone maintaining it.
Object-oriented design works best when classes have single, well-defined responsibilities. A God Object undermines that principle, removing the clarity, modularity that OOP should provide.
I saw an opportunity: while refactoring, I could also migrate the project to the latest PHP version (PHP 5 at the time) and eliminate the mess caused by implicit variable declarations.
To reduce risk, I adopted a blue-green deployment strategy:
- The "blue" environment kept the troubled code running for the client.
- In the "green" environment, I worked on the refa ctored version.
This approach let me keep the application stable while gradually improving the code. The process took longer than expected because I was handling other projects in parallel, but with my supervisor's approval I pressed on. The result was a cleaner, more maintainable system and fewer late-night debugging sessions.
Here are a few recommendations, if you ever find yourself trying to refactor a codebase with God Object:
- Break down its responsibilities into smaller, focused classes.
- Apply principles like the Single Responsibility Principle and separation of concerns.
- Write automated tests to catch regressions as you refactor.
- Use deployment strategies (like blue-green) to minimize disruption for users.
- Refactor incrementally instead of rewriting everything at once. God Objects may feel like a shortcut when speed is the priority, but in reality they slow down development and increase technical debt. My experience taught me that even though refactoring takes time and effort, the payoff is stability, clarity, and long-term productivity.
Short-term hacks might get you past a deadline, but thoughtful design and careful refactoring will carry your software much further.
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