How Analytical Thinking Helped Me Prevent Money Laundering

When we think about analytical skills, the first image that may come to our minds is a scientist working in a lab.

However, in reality, analytical thinking is the ability to cross-reference information and solve problems efficiently. It’s a crucial skill in software development, where making the right decisions can save businesses from financial and security risks.

One remarkable situation where I had to use my analytical skills happened during my last job as a Front-End Developer working at BTG Pactual Bank. The situation involved a serious security risk that could have led to financial fraud.

The Client's Challenge

The client needed a system that processed monthly Excel file uploads containing employee allocation data. However, the data had to be restricted to the current year to prevent fraudulent activity.

Why Was This Restriction Necessary?

🚨 Because allowing data entry for a different year would create a loophole for money laundering.

The spreadsheet contained payment data and sensitive employee information. If someone uploaded a dataset for a different year, they could manipulate financial records and steal money without immediate detection.

Money laundering is a serious crime that involves making illegally obtained money appear legitimate. If someone could submit past or future financial records, they might artificially inflate or shift numbers in a way that disguises fraudulent transactions. Even a minor oversight in software logic could open doors to such financial crimes.

My Solution to Prevent Financial Fraud

To eliminate this risk, I implemented a security measure at the system level:

✅ I locked the year filter so users couldn't manually change it.

✅ I embedded the current year in the API request, ensuring the user had no control over it.

✅ The system automatically retrieved the current year and sent it securely to the backend.

This meant that no user action could override or manipulate the year value. The backend received only the correct year from the system, eliminating the possibility of human interference.

The Technical Approach

On a technical level, the solution seemed simple, but it had a significant impact:

1️⃣ Lock the calendar filter for read-only access – This prevented users from selecting or modifying the year field manually.

2️⃣ Attach the year information to a REST API request – Using Axios, I made sure that the correct year was always sent to the backend.

3️⃣ Securely transmit the request via HTTPS – Ensuring data integrity and security while preventing unauthorized tampering.

This "simple" yet powerful fix prevented a potential financial disaster, saving the company from possible fraud.

Why This Matters

As developers, our job is more than just writing code. We need to anticipate risks and safeguard our clients from potential losses. A poorly designed system can create vulnerabilities that bad actors might exploit.

Without the right safeguards, financial fraud can go unnoticed for months or even years. That’s why understanding the business rules and identifying weak points in a system is just as important as writing clean code.

🛠️To build secure and effective applications, developers should:

🔍 Understand the client’s business niche – Every industry has specific security challenges. Knowing how money flows through a system helps in identifying loopholes.

📜 Learn the business rules – Understanding how transactions are processed ensures that your software aligns with legal and regulatory requirements.

🧐 Analyze user behavior – Both online and offline interactions can reveal potential security risks. By tracking user behavior, you can spot anomalies before they become problems.

Real-World Consequences of Poorly Designed Systems

Many major financial scandals in history have been the result of loopholes in accounting systems. Fraudsters find ways to manipulate transaction records, payrolls, and expense reports. If software is not designed with fraud prevention in mind, companies can lose millions of dollars.

For instance, one of the biggest corporate fraud cases involved a company falsifying past financial records to inflate their revenue. If proper data validation had been in place, it could have been prevented.

Lessons for Developers

💡 Preventing chaotic situations is more valuable than writing complex code.

A software system must be resilient, secure, and aligned with business rules. When designing an application, always ask:

✅ Can users manipulate sensitive fields in unintended ways?

✅ Are API requests validated before processing financial transactions?

✅ Does the backend enforce strict data integrity rules?

By considering these aspects, you not only write good code but also create robust, fraud-resistant applications.

The Key Takeaway

Technology is just a tool—what truly matters is how we use it to solve real-world problems. Writing complex code for the sake of complexity doesn’t make sense if it doesn’t solve a business issue efficiently.

Whether you are a developer, project manager, or entrepreneur, always think ahead and anticipate risks. Solving predictable issues before they occur is what separates great professionals from the rest.

Laura Oliveira

Mobile Developer and Content Creator

Fascinated by technology since she was a teenager, she loves solving problems and learning new things.

I currently work bringing ideas to life for Android apps.

I have +2 million people impacted through the production of digital content.

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