Engineering Growth: Building flexible, scalable payment infrastructure

Scaling a digital platform, particularly in fintech, isn’t just a matter of writing clean code or launching fast. It’s about building with intentionality: creating systems that solve real problems today while being adaptable for the opportunities (and surprises) of tomorrow.

In this article, Eno Ekanem, Head of Solution Architecture at Zest, walks us through what it means to truly “solution for customers,” how we design platforms to be flexible for scale, and the key principles we rely on when building payment systems from the ground up.

In product conversations, especially in startups, “solutioning” can easily become shorthand for “building fast.” But true solutioning means understanding your customers deeply enough to solve not just what they’re asking for, but what they actually need. In my years of leading technical strategy and engineering teams in the payment space, one core truth has remained: sustainable growth begins with building the right foundation.

At its core, solutioning is about empathy. It involves:

• Listening to context: What pressures are your users facing? What is the ecosystem they operate in—regulatory, operational, market-wise?

• Mapping the jobs-to-be-done: A helpful framework I often use is Clayton Christensen’s "Jobs to be Done" theory—understanding what customers are “hiring” your product to do. For example, when a merchant uses your payment API, is their real goal to receive money, or is it to reconcile transactions at scale, automate accounting, and prevent fraud? These are very different jobs, even if they look similar on the surface.

• Proposing value, not just features: Customers often articulate problems as “I want a dashboard” or “I need an API,” but the real opportunity is to surface unmet needs. When building for scale, the goal isn’t to check boxes—it’s to drive outcomes.

In practice, this means co-creating with your early users. Involve them in pilots. Run limited releases. Let them break your assumptions early.

True product-market fit is a conversation, not a feature set.

One of the biggest threats to scale is rigidity. Platforms that work perfectly at 1,000 users often buckle at 100,000. This is rarely a function of infrastructure alone. More often, it’s the result of assumptions baked into the architecture.

So, how do we build flexibility from Day One?

In a platform’s early life, it's tempting to build features as monoliths for speed. But technical debt accrues fast. Startups that scale well usually adopt service-oriented or event-driven architecture early, decoupling:

• Authentication

• Payment processing

• Notifications

• Reporting

• Reconciliation

• Support

This allows you to scale parts of your system independently, onboard different teams more quickly, and avoid re-architecture when new verticals emerge.

If your goal is regional or global scale, design for multi-tenancy—the ability to support multiple clients, users, or brands in isolated but centrally managed environments. Likewise, plan for localization early: different currencies, payment methods, and regulatory requirements.

We’ve seen this especially in African markets where mobile money and card networks differ by country. Having modular payment adapters, flexible fee models, and a permissions-based admin system are not luxuries, they’re critical paths to growth.

When your product serves startups and enterprises alike, you’ll need flexibility in workflows. Features like dynamic pricing, role-based access, feature toggles, and webhooks allow your customers to shape the platform to their processes, without needing one-off code from your team.

Payment platforms are a special breed. They sit at the intersection of trust, security, regulation, and experience. From my perspective, the following are non-negotiables when building for this space:

You’re not just storing data—you’re handling money. Threat vectors are high, and so is the cost of failure.

Implement layered security:

·       Tokenization of sensitive data like PANs

·       Encrypted storage and transit

·       Role-based access controls

·       Logging and audit trails for sensitive actions

·       Regular vulnerability testing and compliance checks

Security is not a checkbox—it’s a mindset that must be shared across all verticals and teams.

Navigating regulations like KYC, AML, and data residency shouldn’t be seen as hurdles—they are opportunities to build user trust.

Embed compliance into your onboarding flows. Provide transparent audit trails. And partner with legal/compliance teams early in your product planning. You’ll go faster long term.

Payments fail. Networks time out. Issuers decline. Users fumble. Great platforms don’t pretend this won’t happen—they plan for it:

·       Use idempotent APIs to handle retries safely.

·       Design clean error codes and messaging for end users and developers.

·       Create dashboards for operations teams to investigate and resolve issues.

Your resilience is not judged on how rarely you fail, but on how well you recover.

If you’re new to this space, welcome. It’s one of the most rewarding—and demanding—areas in tech. Here are a few recommendations I’d share:

Too many developers jump into building without deeply understanding the user problem. Don’t just be a coder—be a problem solver. Read up on product thinking, service design, and behavioural economics. Ask why three times.

Elegant code is not always simple for others to understand. Build systems that your team can onboard onto easily six months from now. Write documentation. Automate onboarding. Keep interfaces clean.

Every feature has a lifecycle: onboarding, use, edge cases, support, and deprecation. Don’t build features—build journeys. Anticipate how your product will evolve and structure it accordingly.

You’re entering a field with constant change: new payment rails, evolving regulations, and new fraud patterns. You will stumble, you will make mistakes. Just never stop learning and keep translating what you’ve learned into improving your processes. Join forums. Learn from others, and teach what you know.

“Building for scale” is ultimately a long-term commitment to resilience, relevance, and responsibility. It’s about balancing customer needs today with the flexibility to evolve tomorrow. Whether you’re building for a neighbourhood business or the next billion-dollar startup, the principles remain the same: solve real problems, design for adaptability, and never compromise on trust.

As solution architects and product builders, we have the opportunity—and the responsibility—to shape the financial infrastructure of the future.

Let’s build boldly, but wisely. 

Eno Ekanem leads solution architecture at Zest Payments Limited, the fintech subsidiary of Stanbic IBTC Holdings.

To enjoy a customizable payment infrastructure that fits right into your operations, get started by sending an email to partnerships@zestpayment.com