USSD: The Unsung Hero Driving Innovation in a Connected World

Technology

Explore USSD, the often-overlooked mobile technology, powering essential services and massive digital economies in regions with limited internet. It's about suitable innovation, not just shiny tech.

By Werner Vogels

What is USSD (and who cares)?

October 29, 2025 • 1140 words

Imagine Lagos: the city hums with activity, the heat is palpable, and you're en route to an important meeting. You hail a cab, and upon arrival, pay seamlessly with your phone. The driver confirms the payment instantly on his device, then transfers money to his mother in Abia – all via his phone. Thousands of kilometers away in Nairobi, a mother returns home from work to find her bioethanol supply for dinner is low. She heads to a KOKOpoint – an ATM for cooking fuel – to top up her bioethanol, again, using just her phone. Remarkably, all these interactions occurred without an internet connection, utilizing hardware costing less than $20 USD.

(Image source: Michael Hanscom)

If you recognize these older phones, it's likely you last encountered USSD (Unstructured Supplementary Service Data) through them. Activating a SIM card, checking your balance, topping up minutes, purchasing a ringtone, or making charitable donations were all facilitated by USSD (not to be confused with SMS). This standard, developed in the early 90s as part of the GSM Technical Specification, enabled real-time, session-based communication between mobile devices and mobile operator network services via simple, menu-driven interfaces.

For those unfamiliar, here’s a high-level overview of how it works: A feature phone user initiates a request (e.g., *123#). This message travels through their mobile network to a USSD gateway, which routes the request to the appropriate application server based on the short code. The server then responds via the same path, presenting a menu for the user to interact with. It's a stateful session with brief timeouts, but it's fast, cost-effective to operate, and requires only 2G connectivity.

(Image source: Somtochukwu Anunobi, Staffordshire University)

The advent of internet-connected smartphones led many of us to abandon USSD in favor of modern interfaces that mirrored desktop experiences, eventually evolving into today's mobile-first designs. Banking is a prime example of this shift; when was the last time you wrote a check? We now move money so frequently and effortlessly through traditional bank accounts and digital wallets (Venmo, Cash, Zelle, Tikkie) that it's hard to conceive of alternatives. Yet, vast populations globally still lack access to reliable internet or smartphones. In Sub-Saharan Africa, mobile internet penetration hovers at just 27%. What they do have, however, are feature phones—and plenty of them.

Instead of allowing access or hardware to be a limitation, hugely profitable businesses like M-Pesa, Moniepoint, Mukuru, and OPay have ingeniously leveraged USSD—an old, yet ubiquitous messaging standard—to create front-ends for user transactions that rival the scale of their Western counterparts. In 2024 alone, M-Pesa processed over $100 billion, while Moniepoint handled 5.2 billion transactions worth $150 billion.

To be clear, these companies are not stuck in the past. Behind those simple USSD interfaces, they are building sophisticated cloud architectures. M-Pesa employs machine learning for real-time fraud detection, managing 4,000 transactions per second, with Safaricom utilizing AWS for its cloud infrastructure. KOKO Networks operates what's recognized as Africa's largest deployment of IoT technology for consumer fuels; its 700+ fuel stations are connected to a cloud platform, sending real-time inventory data and enabling demand forecasting. This is not a narrative of technological limitations causing hardship. It’s a testament to builders focused on technology that is suitable, not merely shiny.

"The limitations of materials are honesty in design. What you can't do is as important as what you choose to do." - Santiago Calatrava

While the ultimate goal of sub-$100 USD smartphones and universal connectivity is admirable, it doesn't reflect today's reality. Fifty-five percent of mobile users in Sub-Saharan Africa rely on 3G, and estimates suggest that a third of connections will still be 3G in 2030. Hundreds of millions of people cannot wait for technology to catch up to their daily needs; they need to buy groceries today, not tomorrow, and fuel this week, not at month-end. As long as this gap persists, builders who grasp this urgency will continue to find ways to bridge it with tools that genuinely work for their communities—and they will profit while doing so. Though not always evident, this is technology for good.

Some closing thoughts

Many of us are familiar with the acronym KISS: Keep It Simple, Stupid, a phrase originating from the US Navy in the 1960s. Personally, I don’t favor it. Simplicity is challenging, and not getting it right on the first attempt doesn't make you stupid. However, I firmly believe that as builders, we must be relentless in asking: Are we truly keeping things simple for our customers? Simple to maintain? Simple to update? Simple to explain?

Consider a car. Under the hood, it’s a complex machine—a blend of mechanical and electronic components, sensors, and computers, all working in harmony.

(Image source: EE News Europe)

Yet, for the driver, the interface has remained largely unchanged for nearly a century: a wheel, mirrors, pedals, and a shifter (plus a clutch for manuals). You don’t need to comprehend fuel injection or anti-lock braking to reach your destination. The same principle applies here. USSD might appear primitive compared to a smartphone app, but it functions on every phone, requires no data plan, and your grandmother can use it without an in-depth tutorial.

Not everything requires engineering to the level of Apollo 11’s guidance computer. While it stands as a pinnacle of constraints-driven design, using a mere 4KB of RAM to safely transport astronauts to the moon and back, that was bespoke engineering for an extraordinary mission. The best engineering seamlessly integrates into everyday life. You don’t ponder driving your car or paying for groceries. No one writes headlines when money is sent from Lagos to Kigali or a file is uploaded to S3. When technology performs so effectively that it becomes practically invisible—that’s arguably the highest compliment it can receive.

As builders, our role is to abstract away complexity and devise elegant solutions for difficult problems. When we get it right, it can be truly beautiful. However, we must resist the temptation to engineer for engineering's sake and always work backward from the needs of our customers.

That's why the developments in Sub-Saharan Africa are not just regionally impressive; they offer a blueprint for building more resilient, efficient, and cost-aware systems anywhere in the world.

Now, go build!

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