My Experience as a Lead Software Engineer at Unbanked

Imagine this: you swipe a card to buy coffee, but instead of dollars, you use your own digital money, like crypto. This sounds like a movie, but it was real! At Unbanked, I worked for two years helping to make digital money easy to use, just like regular money in your wallet.

For a long time, cryptocurrency was separate from regular life. You could own it and trade it, but you could not spend it on groceries or shoes. Unbanked solved this problem. We partnered with companies that had digital money and gave them a special debit card. This card let their customers spend their digital money anywhere, like a normal card.

Starting the Journey

I joined the team as a lead engineer. My job was to connect partners like StormX and Zebec to our system so they could offer cards to their users. I led small teams of three to six people.

We had one main goal: work fast. In crypto, partners do not want to wait. We needed to find a way to connect new partners in minutes instead of weeks.

Creating a Plugin Integration System for new Partners

At first, it was not easy. Every time we added a new partner, it took two full weeks of hard manual coding work. I designed and built a new framework from the ground up, an asset plugin system. Instead of writing custom code for each partner, this system created a universal adapter that could connect any partner’s token in just a few minutes.

The plugin system worked by using a standard setup. Any partner could define their token properties, and the system would automatically connect them to our debit card infrastructure, transaction processing, and wallet management. We went from two weeks per partner to minutes per partner.

This massive speed improvement let us onboard major partners across Ethereum, Solana, and Stellar networks. What took a full sprint before could now be done before lunch.

Connecting to the Solana Network

Zebec was a major company on the Solana blockchain, and they wanted to work with us. I led the project to connect our entire system to Solana. This was a big challenge because Solana is a different blockchain than what we used before.

I built a polling system, a program that continuously watches the Solana network for new transactions sent to us. I also set up proxy wallets to hold and manage the money safely. Using the @solana/web3.js library, we built the full bridge to this new blockchain.

The result was major: we added support for USDC (a stablecoin) for all Zebec users and added support for SOL (Solana’s native token) to the entire Unbanked program. This single project opened up an entire new blockchain ecosystem and made our platform much more valuable.

Building Better System Architecture

I designed and built a webhook subsystem to send automatic notifications to our partners whenever important events happened, like transactions. This kept them updated in real time. I also created a socket strategy for direct, instant communication between our system and partners. The tricky part was managing load balancer routing to make sure messages always reached the correct partner.

I also improved how our system handled background jobs and events. I used Bull (a task queue library) with Redis, a super-fast database, to manage all the jobs our system needed to do. I carefully optimized the Redis connections so just a few connections could handle thousands of jobs. This made the whole platform faster and more reliable, able to handle massive growth.

Building a Testing System

Quality was critical, especially with money involved. I built a virtual card terminal that could simulate every possible purchase scenario. This system tested transaction flows, error handling, edge cases, and settlement processes before anything went live. We could test thousands of different scenarios automatically. This meant we caught problems before customers ever saw them.

Implementation was complex. I created a full simulation environment that mimicked real-world payment terminals mocking the API of Cashpass and Tribe.

Integrating KYC and Compliance

Following the law is critical in finance. I led the integration of a top-tier KYC (Know Your Customer) provider into our system. This meant building secure connections to verify user identities and ensure we met all regulatory requirements. I created a smooth process that was fast for both users and our team. This integration kept us legally compliant while building trust with partners and customers.

The Results

The impact of all this work was major:

• Millions in Revenue: The plugin system, blockchain integrations, and transaction processing infrastructure we built generated millions of dollars for Unbanked.
• 30,000+ Users Empowered: Over 30,000 people could finally spend their digital tokens and crypto in the real world using our debit cards.
• Major Infrastructure: We built a fast and reliable platform that could handle thousands of transactions per day with support for multiple blockchains (Ethereum, Solana, Stellar) and token types.
• Extremely High Quality: We reduced payment settlement errors from 10% down to less than 0.1% (a 100x improvement!) through our virtual card terminal testing and system improvements.

The End

Working at Unbanked was incredible. We were growing fast and building innovative crypto payment infrastructure. But when a promised multi-million dollar investment fell through, the company had to close.

However, what we built was real and lasting. We created a plugin system that reduced integration time from weeks to minutes. We connected multiple blockchains and made a platform that handled thousands of daily transactions. We helped 30,000 real people spend their digital money in the real world. I learned that I can solve complex technical problems, lead engineering teams, and build products that make a real difference. That experience shaped who I am as an engineer today.