The founder had a plan. A clean plan. A beautiful plan.
"We're going to rewrite everything," he told me, eyes bright with possibility. "New code. Clean architecture. Modern stack. Everything we've learned, applied fresh."
I asked him how long the original product had taken to build. Eighteen months.
"How long for the rewrite?"
"Six months," he said confidently. "Maybe less. We know what we're doing now."
I nodded and asked the question I always ask: "What happens during those six months?"
Silence.
Because during those six months, the old product still needs maintenance. Bugs still need fixing. Customers still need support. Features still need shipping.
And during those six months, nothing new gets built on the old codebase—because everyone knows it's getting thrown away.
That's how rewrites work. They don't move you forward. They pause you, then move you sideways.
The Rewrite Fantasy
Every founder who has struggled with a legacy codebase has dreamed of the rewrite.
The new codebase will be clean. The new architecture will be elegant. The new code will be maintainable. The new team will be productive.
The old codebase is a mess. The old architecture is spaghetti. The old code is unreadable. The old team is constantly fighting fires.
The rewrite promises redemption. A fresh start. A chance to do everything right this time.
But that's not how it works. That's not how any of this works.
What Actually Happens
I've watched dozens of startups attempt rewrites. Here's the pattern:
Month 1: Enthusiasm. The new codebase is beautiful. Everything is clean. The team feels like they're finally doing it right.
Month 2: Feature requests on the old system. The team has to maintain two codebases now. Progress on the rewrite slows.
Month 3: Discovery. The old system has features that nobody remembered. Edge cases that weren't documented. Integrations that were assumed but never written down.
Month 4: Compromise. The new system needs to match the old system's behavior. "Just this one feature," becomes "just these ten features." The new architecture gets bent to accommodate reality.
Month 5: Deadline pressure. The rewrite was supposed to take six months. It's now month five and they're not close. The team cuts corners to catch up.
Month 6: Launch... of a system that's almost as messy as the original, but without the battle-tested reliability.
The Two System Problem
Here's what nobody tells you about rewrites: you now have two systems.
The old one, which still runs your business. The new one, which isn't quite ready but everyone is tired of working on.
For months, you're maintaining both. Every bug fix has to be applied twice. Every new feature has to be built twice. Every integration has to work with both.
That's not doubling your work. That's multiplying your complexity.
A startup I worked with spent eighteen months on a rewrite. During that time, their main competitor launched three major features and captured significant market share. The rewrite shipped, but the market opportunity had moved on.
The Knowledge Loss
Every line of code in your existing system represents a decision. A decision that was made, tested, and refined through actual use.
The "spaghetti code" you hate so much? It works. It handles real user behavior. It accounts for edge cases that users discovered. It has workarounds for problems that were actual problems at the time.
When you rewrite, you lose all that knowledge. Not all of it is documented. Not all of it is remembered. Some of it lives only in the code itself.
I've watched startups rewrite systems and discover, months later, that they were relying on behaviors that existed in the old code but were never documented. Behaviors that users depended on. Behaviors that the business relied on.
The Rare Exception
I'm not saying rewrites are never appropriate. There are rare situations where they make sense:
When you're changing platforms entirely and the old code is worthless on the new platform. When the technology is so old that no one can maintain it anymore. When the business is pivoting so dramatically that nothing carries over.
But even in these cases, the rewrite should be scoped to what's truly necessary. Not "rewrite everything." Just "rewrite what's required for the new direction."
The Alternative: The Strangler Pattern
Here's what smart teams do instead: they strangulate the old system.
Identify a component. Build a new version. Route some traffic to it. Verify it works. Repeat.
Slowly, gradually, the new system replaces the old. But the old system stays running the whole time. You can roll back if something goes wrong. You can take as long as you need.
A fintech startup I worked with strangulated their payment system over two years. They never had a "rewrite." They just replaced one piece at a time, always keeping the old system as a backup, always being able to roll back.
It took longer than a rewrite would have. But it was safer, and they never lost business continuity.
The Real Problem
The temptation to rewrite is usually a symptom of a different problem.
The real problem might be that no one understands the codebase anymore. The solution isn't to rewrite—it's to document, refactor, and share knowledge.
The real problem might be that the architecture doesn't support new features. The solution isn't to rewrite—it's to refactor the specific components that are blocking you.
The real problem might be that the team is frustrated and demoralized. The solution isn't to rewrite—it's to fix the process and culture issues that are causing the frustration.
The rewrite is the symptom, not the disease.
The Bottom Line
Rewrites feel like progress. They feel like a fresh start. They feel like finally doing things right.
But they rarely are.
They consume time you could spend growing. They risk knowledge you've built. They pause your business while your competitors keep moving.
Before you rewrite, ask yourself: What problem am I actually solving? Is there a smaller, safer way to solve it?
Most of the time, there is.
Need Help Evolving Your System Without Rewriting?
At Startupbricks, we help startups improve their systems incrementally. If you're tempted by the rewrite fantasy, let's talk about safer alternatives.