Critical Software design decisions: The pros and cons of using a 'big ball of mud' software architecture.

Critical Software design decisions: The pros and cons of using a 'big ball of mud' software architecture.

Critical Software design decisions: The pros and cons of using a 'big ball of mud' software architecture.


If you are in the software industry, you’ve probably seen the typical “big ball of mud” software architecture.

A “big ball of mud” comes from an unplanned system accreting piles of unstructured, inconsistent, and tangled code over time without a clear direction or design.

“Big ball of mud.” The most pervasive software structure on the planet.

The main problem with the big ball of mud is that while it’s common, cheap, and fast to write initially, it’s expensive to own.

Maintenance challenges may be especially troublesome for companies trying to grow their business quickly.

If your software has no structure or designs for extensibility, you won’t be able to add new features easily or expand on your existing product; instead, you’ll likely have to throw out everything you’ve done so far and start over again.

This lack of structure also means that big balls of mud are brittle: if you need a change down the road, there may not be an easy way for an engineer to implement it without breaking something else.

The pro of the big ball of mud architecture: it’s easy to start.

The primary advantage of this architecture: it’s easy to get up and running fast.

Imagine you’re just getting started with a new project. Without experience, it’s quicker to jump in and start hacking away at things instead of spending decades learning how to structure a solid foundation.

You rocket forward by short-circuiting traditional investments. You short-circuit design, documentation, and code quality constraints.

And bypassing deliberate design liberates you from a lot of overhead.

  • You minimize the training required because there are no formal conventions, standards, or structures.
  • There’s no point in investing in peer-reviewed code because you are explicitly trading speed for quality.
  • And there’s no comprehensive testing of your application before it goes live (though you may want to kick the tires to be sure it doesn’t collapse).

The cons of a big ball of mud architecture: maintenance is expensive to own, and it’s hard to keep it running without a complete rewrite.

The big ball of mud architecture is difficult to maintain.

It’s hard to make changes, add new features, and test. Even if you can get past that, owning a big ball of mud architecture in production is an expensive, risky, and stress-inducing headache because you own an unstable, overly complex, and untestable system wrought with defects.

When you ship to production, most, if not all, of your engineers frequently get pulled off feature development for firefighting.

Consider cost/benefit tradeoffs between initial construction speed and maintenance costs.

Technical product owners must use their judgment to balance cost/benefit tradeoffs.

You can have fast initial construction speeds with high maintenance costs or take the time for more deliberate design to prevent problems tomorrow.

It’s important to note that the big ball of mud architecture is not a cure-all to avoid design. It frequently fails when fragility, quality, and maintainability issues cause an ownership cost explosion.

But it gives you options in the right circumstances. For example, A Big Ball of Mud is a perfect fit when you want to experiment.

While not great for production systems, it shines brilliantly when testing new technologies or doing quick experimental spikes to discover a solution.

So while only a good fit for some specific situations, with the proper aim, it’s worth considering as an option.

Even structured systems decay into big balls of mud

Entropy is a powerful driving force in software systems because they constantly change.

Having a design is not a guarantee against decay because, without a plan, structures can devolve into a ball of mud.

And while organized systems are initially easier to maintain, they are not resistant to decay without deliberate, intentional, and professional design for rot prevention.

Think of it this way: Slinging code takes one skill level. It takes leaps in skill and discipline to stay organized.

And it takes much deeper engineering expertise and architectural acumen to design rot-resistant infrastructure using professional-grade architecture patterns.

To prevent code from rotting into a big ball of mud, you must deliberately design for change.

Use good judgment and experience to decide whether a big ball of mud architecture meets your software project objectives.

Use good judgment and experience to determine whether the advantages of a big ball of mud architecture meet your objectives or if you want to avoid the downsides.

If you’re building a small experimental project that you’re happy to scrap tomorrow, you may care about something other than designing for quality, sustainability, and longevity.

However, if you’re investing in building customer-facing projects, consider safeguarding your future with professional architecture.

Do you want to prevent your system from decaying into a big ball of mud? If so, you’ll need deliberate upfront design and careful monitoring of code debt to avoid exploding maintenance costs, production system failures, and headaches.


Because of a lack of skilled software architects in the market who know how to design for future change and the nature of rapid evolution driving software decay, the “big ball of mud” architecture is widespread today.

You’ll frequently see big balls of mud in production throughout your career.

However, many times it’s entirely up to you.

You can use good judgment and experience to decide if it’s worth an investment in sustainable design.

You’ll also decide on a maintenance strategy. Prevention is not free, and either way, you’ll likely pay. So you have to decide today if you’ll let your systems decay.

When things slide down into the mud, watch your back, track your maintenance costs, and know when to rewrite!

Best wishes and warmest regards — Matt

By the way…

Watching software rot is a frustrating experience. You invest in application development only to see your structures slowly dissolve and disintegrate.

Think of it like building a bridge. You don’t need a degree in civil engineering to know that if you want to prevent rot, you’ll have to invest in something that doesn’t work against you but supports your needs.

Take a look at Applinate—Truth Shield’s open-source. NET foundational (micro) service architecture.

With intentional design:

  • To resist software rot, with clear boundaries to facilitate constant change,
  • With easy conventions to separate concerns and contain the impact of change
  • To provide extensibility points in the right places to guide coders toward making good decisions.

Applinate is perfect for accelerating projects of any size and upgrading legacy .NET systems with a superior development experience for easy maintenance.

At the same time, Applinate meets best practices for large-scale enterprise software design: providing a clean architecture, solid modularity, loose coupling, distributed, highly scalable, and rot-resistant foundation to extend the life of your systems.

So you get the best of both worlds: rapid prototypes that can survive, scale, and thrive in production, and your production systems stay supple, extensible, and maintainable.

Want to avoid software decay? Either invest in professional-grade design or use ours. You’ll be happier in the long run.

Control your fate; click here now to check out Applinate.