Most business logic ends up hardcoded deep in your app, and it’s slowly killing your codebase.

What starts as a clean service grows into a bloated mess of if-else statements, feature flags, and ad-hoc patches no one dares touch. Before long, your services are “absolute units”, ORM models do way more than map data, and you’re moving data back and forth like an unpaid intern, not a software engineer.

How did we get here?

The real problem: Business logic is treated like an afterthought

When was the last time you saw business rules treated with the respect they deserve? Instead, here’s the all-too-common scenario:

• A product manager vaguely defines a feature
• Developers rush to ship because “deadlines”
• Business rules get buried inside controllers or, worse, the database
• Tests? What tests?

Why? A few reasons:

• Broken hiring practices: We value knowing 17 JavaScript frameworks but rarely test problem-solving or domain understanding.
• No architecture, just vibes: Clean, hexagonal, or onion architectures are skipped because they “take too long.”
• Chronic time pressure: Everything’s urgent, so corners get cut. “We’ll clean it up later”, but later never comes.
• Developers as ticket machines: We’re told not to question the “why,” just implement what’s in the JIRA ticket. But here’s the kicker: even the business doesn’t know the exact logic upfront.

Business logic is a moving target

Most businesses don’t hand you a perfect spec.

What they think they need changes after UAT (User Acceptance Testing) and honestly, sometimes they’re still figuring it out.

The result? Developers get stuck fixing logic mid-flight. And when change requests hit, it’s like performing surgery on spaghetti.

Why? Because the business rules (pricing logic, eligibility criteria, workflow paths) are scattered all over your codebase, database, and feature flags.

Why hardcoding business logic is a long-term trap

Hardcoding logic into your app feels fast… until:

• You need to support a slightly different flow for one client
• A manager wants to tweak a rule without a dev deploy
• Regulations change, and now your pricing logic is illegal
• Feature flags explode into an unmanageable decision tree of doom

Every time, you patch it “just one more time” until your once-beautiful microservice is a ball of mud.

Feature flags will only get you so far

Yes, feature flags help temporarily. But try scaling 50+ flags, each with nuanced conditions.

It turns into an unmanageable matrix where no one understands what’s live anymore.

So what’s the solution?

Treat business logic as a first-class citizen.

It doesn’t belong:

• Hardcoded in services
• Hidden in database triggers
• Strewn across dozens of feature flags

Instead, consider:

• Using a Decision Engine: offload complex conditions to a system designed for business rules
• Adopting Rule-as-Data patterns: store business rules externally and version them like any other critical asset
• Creating a Business Logic Layer: make it explicit, tested, and documented
• Empowering analysts or product owners to tweak rules without requiring a developer

Example: hardcoded business logic vs. externalized rules

Let’s say you’re building a loan application system. Here’s what typically happens:

❌ Hardcoded business logic (the wrong way):

def evaluate_application(application):
    if application.income > 50000 and application.credit_score > 700:
        return "Approved"
    elif application.income > 30000 and application.credit_score > 650:
        return "Pending - Needs Manual Review"
    else:
        return "Rejected"

It works... until the business wants to:

• Change income thresholds
• Add location-specific rules
• Adjust for new credit scoring models

Now you’re shipping a new version just to change a number.

✅ Externalized business rules (the better way):

rules = load_rules_from('rules.json')

def evaluate_application(application):
    for rule in rules:
        if rule.matches(application):
            return rule.decision
    return "Rejected"

Where rules.json contains:

[
  { "income_min": 50000, "credit_score_min": 700, "decision": "Approved" },
  { "income_min": 30000, "credit_score_min": 650, "decision": "Pending - Needs Manual Review" }
]

Solving This Problem with SmartDecision

This exact pain point is why we’re building SmartDecision: a Business Rule Engine (BRE) designed to help teams manage complex business logic outside the codebase.

• Write rules in plain language
• Version and test logic like any critical asset
• Empower product managers or analysts to tweak decisions without shipping new code
• Keep your core application clean and maintainable

If you’re tired of drowning in feature flags and if-else chains, check it out. SmartDecision is built to fix this exact problem.

👉 Learn more about SmartDecision here.

Conclusion

Software is supposed to change, especially the business logic. That’s the point of software. So why do we write it like it’s set in stone?

Next time, pause before coding the logic into your app. Think about what happens when (not if) the rule changes. Build systems that respect the dynamic nature of business rules. Because the fastest way to slow down your development… is to hardcode decisions that will absolutely change.