Why I Plan Before I Code

In my 3.5+ years of building fintech systems, I've learned one crucial lesson: the most expensive bugs are design bugs, not code bugs.

The Cost of Not Planning

I've seen teams jump straight into code, only to discover weeks later that their data model can't support a critical use case. At that point, you're not fixing a bug — you're rewriting a system.

My Planning Process

1. Understand the Domain

Before touching the keyboard, I spend time understanding the business domain deeply. When building the bond trading system, I studied:

• How RFQs work on NSE
• Settlement cycles and their edge cases
• Payment flow compliance requirements

2. Design the Data Schema First

The schema is the foundation. If your schema is wrong, everything built on top will eventually break.

// Example: RM Hierarchy using Nested Set Model
{
  rm_id: "RM001",
  name: "John Doe",
  left: 1,
  right: 14,
  depth: 0,
  // All descendants have left > 1 and right < 14
}

3. Map the API Contracts

Before implementation, I define every API endpoint, request/response format, and error code. This becomes the contract between frontend and backend teams.

4. Consider Scale from Day One

At GoldenPi, we serve 400K+ customers. Every feature I build considers:

• Database query performance at scale
• Concurrent request handling
• Async processing for heavy operations

The Payoff

Features built with this approach are:

• Bug-free at launch — edge cases are caught during design
• Easy to modify — clean abstractions make changes straightforward
• Easy to understand — new developers can onboard quickly

The extra planning time pays for itself many times over.