Why Your Phone Still Fails You When You Land Abroad, and the Engineer Trying To Fix It

Aqib Hassan spent years studying how networks break. Now, as CTO of HelloRoam, he is trying to solve one of travel's most persistent annoyances.

Almost every international traveller knows the moment. The plane lands, phones come out, and then nothing loads. Some passengers switch on roaming and hope the bill won't be too bad. Others look for airport Wi-Fi so they can find out how to get to their hotel.

A few join the queue at a SIM kiosk, passport in hand, trying to compare data plans in a currency they haven't worked out yet.

Phones now handle boarding passes, payments, maps and translation, so it's odd that getting a phone online in a new country is still so clumsy.

Aqib Hassan has thought about that more than most. He is co-founder and chief technology officer of HelloRoam, a travel eSIM company that launched in March 2026. In about seven months, its app has passed 55,000 downloads and its plans cover more than 185 countries.

'People assume the hard part is selling data. It isn't,' Hassan said. 'The hard part is making something that behaves differently in every country feel identical to the person holding the phone.'

A Researcher's View of the Problem

Hassan came to the problem from research rather than from the travel industry. He completed a master's degree in computer science, specialising in Network Engineering, at the University of Greenwich in London.

His postgraduate work looked at how machine learning could spot malicious traffic inside computer networks: in effect, teaching software to notice when something on a network wasn't behaving as it should.

His research then moved into forecasting. He co-authored peer-reviewed papers, published by IEEE and Elsevier, on deep-learning models for wind energy prediction and on hybrid neural networks for short-term electricity demand forecasting. His work has received around 70 Google Scholar citations from other researchers.

Energy grids and mobile data look unrelated, but Hassan sees a common thread. Both are systems where supply, demand and conditions change constantly, and where small failures quickly reach the end user.

'Research taught me to ask why something fails before asking how to fix it,' he said. 'That habit turned out to be more useful in a start-up than any particular algorithm.'

Learning To Ship

Research moves slowly. Hackathons don't.

At Encode ETHLondon 2023, Hassan worked on BossVault, a blockchain project that won an Etherspot-sponsored bounty worth $1,500, followed by an additional $150 voucher.

A year later, at ETHGlobal London 2024, he built 0xEstate, which took third place and a $1,000 prize in the Uniswap Foundation's Best Use of Hook Features category. It also won a Worldcoin Pool Prize.

These events give teams about a weekend to find a problem, build working software and defend it in front of judges. Hassan says they changed how he approaches products. You can't spend 48 hours polishing an idea nobody needs, so you learn to start from the problem rather than from the technology.

Travel connectivity was the problem he kept returning to.

What an eSIM Actually Has To Do

An eSIM is a digital SIM profile that a traveller downloads to a compatible phone instead of inserting a plastic card. In principle, you buy a plan before you fly and your phone connects when you land.

In practice, Hassan says, the simplicity is something engineers have to build. Behind each plan HelloRoam sells are network operators in different countries, wholesale prices that change without warning, data allowances and validity periods that vary by market, and phones that handle eSIM installation in slightly different ways.

As CTO, Hassan designed the systems that hide that complexity. They include HelloRoam's web platform and mobile apps, the backend that provisions eSIMs, and an automated pricing engine that takes in supplier rates and applies the company's pricing rules across its whole catalogue.

When a wholesale price changes in one country, the system adjusts without anyone editing it by hand. The platform now supports 63 languages and more than 31 currencies.

Some of the hardest work is invisible when it goes right. A traveller standing in an arrivals hall won't wait for a support ticket to be answered tomorrow. HelloRoam handles support through WhatsApp and email, and Hassan's team has built internal tools to diagnose activation and configuration problems across different devices and countries while the customer is still waiting.

'Every country is a slightly different puzzle,' Hassan said. 'Our job is to solve it once, properly, so the customer never has to.'

Competing With Bigger Names

The travel eSIM market has become crowded quickly, with well-funded international competitors and growing consumer awareness as more smartphones support the technology. For a young, independent company, passing 55,000 downloads in its first seven months is an early sign that the product is working.

Hassan's role has changed with that growth. He spends less time writing code and more time making architecture decisions and leading the engineers who own different parts of the platform.

He says the trade-offs are different too. Reliability, cost, customer experience and the speed of entering new markets all pull in different directions, and a good technical decision has to account for all of them.

Connectivity as Part of the Booking

HelloRoam's next step is partnerships. The company wants to work with travel agencies, online booking platforms and hospitality businesses so that mobile data can be sold alongside flights, hotels and insurance rather than sorted out at the airport.

If that works, the scene at arrivals could change. Phones would simply work on landing, because connectivity was booked weeks earlier along with everything else.

'Nobody should have to think about mobile data when they travel,' Hassan said. 'If we do our job well, they won't.'

For a researcher who once trained software to notice when networks misbehave, it's a fitting problem: making a messy global network invisible to the people who rely on it.