Konstantin Semenenko
October 11, 2025
8
minutes read
How one mindset can improve everything — from product code to Terraform scripts
Software development isn’t just about writing code.
It’s about designing systems that can survive growth, change, and pressure.
One of the best frameworks for achieving this is SOLID — five timeless principles of clean, object-oriented design.
Originally meant for developers, they also work beautifully for DevOps — helping teams structure infrastructure, reduce friction, and scale without chaos.
In this article, we’ll share a real-world case from Managed Code’s collaboration with a fintech company, showing how SOLID principles shaped both their software and DevOps practices.
You’ll also find key takeaways for MVPs, startups, and scaling teams.
In the early stages, startups move fast — but often without the structure that keeps them stable later.
Following SOLID principles early doesn’t slow you down; it gives your product room to evolve without breaking.
For MVPs, that means:
Skipping SOLID might save a week today — but it costs months tomorrow.
Our client builds enterprise software for banks and financial institutions — from payment systems to analytics dashboards.
As their product suite grew, the same issue appeared again and again:
small changes caused massive ripple effects across modules.
The result?
Our goal was to refactor their architecture — and apply the same SOLID logic to their Terraform-based DevOps pipelines.
Each of the five SOLID principles was implemented step by step — not as a theory, but as a practical engineering method.
Every class, script, or module should do one thing — and do it well.
We split large transaction-processing classes into smaller, focused ones: validation, database logging, and reporting.
This separation simplified testing and debugging, making every piece easier to manage and reuse.
In DevOps, the same logic applied: one Terraform module handled VPC creation, another handled databases, another — CI/CD.
One purpose per unit = no chaos later.
Systems should be open for extension, but closed for modification.
Instead of editing old code to add new payment methods, we introduced abstract interfaces.
Each new method plugged in independently — zero risk to the existing logic.
In DevOps, that meant adding new environments or instance types without touching the main scripts.
Scalable, safe, predictable.
New implementations should work wherever the old ones did.
In practice, subclasses (like new payment gateways or report generators) behaved exactly as their parent classes — fully interchangeable.
That made the code more consistent and reduced unexpected bugs.
Applied to DevOps, it meant we could switch cloud resources — e.g., move from general-purpose to memory-optimized instances — without rewriting the automation.
No class or script should be forced to depend on things it doesn’t need.
We replaced bulky interfaces with smaller, focused ones — for example, separating payment validation, authorization, and notification.
Each module only knew what it needed to know.
The same pattern worked beautifully in Terraform: separate modules for VPC, IAM, and security groups.
No “God scripts.” No hidden dependencies.
High-level modules shouldn’t depend on low-level ones — both should depend on abstractions.
We restructured the architecture so that high-level logic interacted only through defined interfaces.
For example, the payment system didn’t depend on a specific service — it depended on the Payment Provider interface, injected at runtime.
In DevOps, that meant the CI/CD pipeline didn’t depend on one specific deployment script but used abstract deployment layers.
We could switch between blue-green or rolling deployments with zero pipeline rewrite.
After full SOLID adoption, the client saw measurable improvements:
In short — less firefighting, more building.
Most people associate SOLID with developers, not DevOps.
But in modern systems, your infrastructure is code — and it benefits from the same discipline.
Using SOLID for Terraform, CI/CD, and automation helps teams:
The same engineering mindset applies — just at a different layer.
The SOLID principles proved their worth far beyond code.
They became a shared language between development and DevOps — bridging teams, reducing risk, and making change sustainable.
For startups and established teams alike, this mindset means faster iteration today and smoother scaling tomorrow.
At Managed Code, we use SOLID thinking not just in our development process but in how we design systems, data flows, and AI integrations.
Whether it’s backend refactoring, infrastructure automation, or an MVP launch, we help you build systems that last.
Want to see how SOLID can reshape your architecture?
Book a quick call — and let’s build something that scales cleanly.
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