From travel eSIM to Revolut Mobile: inside the team building the experience

There's an experience almost every person who travels knows. You land, turn on your phone, and the first thing you see is a roaming notification reminding you that every message, search, or map you open, all costs more than it should. The traditional fix would be to find a local phone shop, queue up to get a local SIM, explain what you need in a language you may not speak, and hope it works before you catch the metro.

One day at Revolut, someone asked a simple question: what if this were as easy as sending money?

The idea behind eSIM

Elyas Sadou has been with Revolut for over five years. He joined as a junior in strategy and operations and is now Head of Product for the Telecom team. In that time, he's seen the company's growth firsthand.

One of the projects that defines that growth is ‌eSIM. The idea was to connect customers to mobile data in over 100 destinations with a few taps — from the same app where they manage their money, at a fair price. No extra downloads. No phone calls. No queues.

The challenge: no one on the team had built anything like it before.

Building without a map

When the Engineering team got to work, the first thing they discovered was that there wasn't much to lean on. Ruslan, one of the leading Software Engineers, remembers it clearly:

Public documentation was scarce. Many of Android's critical APIs were poorly documented or outright broken on certain devices. And eSIMs don't work on emulators, which meant every test had to be done on real, physical devices.

"We had to run tests across numerous sessions to understand whether a given part of the platform API would behave as expected," Ruslan explains."We wanted to keep customers fully equipped with a smooth experience, with no extra effort on their part."

One of the most ambitious challenges was achieving a one-tap eSIM installation from day one. The team had to go the full distance from scratch, testing across different physical device models to map every possible state during the installation process.

But the technical challenges didn't stop there. Software Engineer Joaquin, describes precisely what no one sees from the outside:

On top of that, Android ecosystem fragmentation. Each manufacturer ships their own OS, and some blocked eSIM delivery entirely. The team built flows that adapted to each device in real time.

The solution wasn't to build something more complex. It was the opposite.

The philosophy behind the code

That translates into concrete decisions. Documentation anyone can understand. Direct communication, no noise — within the team and across teams. Clean, well-tested code built to last, not to be rewritten. The same logic applies at global scale.

"We choose tools deliberately," says Pawel Ochrymowicz, Platform Engineer (Java). "Based on real analysis, not trends. We never stack technology for the sake of it — fewer layers means less latency. We don't build complicated systems to prove we can. We build systems that handle global concurrency and remain understandable."

The result nobody expected

When Revolut introduced eSIM access in-app, something happened that the team hadn't fully anticipated. Customers adopted it en masse.

In 2024, Revolut became one of the first fintechs to bring global eSIM access to its customers. Since then, customers have activated millions of data plans across 100+ destinations. Today, eSIM is the most popular non-financial feature available through the Revolut app.

The project won the 10X Award, one of the most significant internal recognitions at Revolut. For Elyas, that recognition means something specific: "It's a great achievement for the team, for every function that was involved. Designers, developers, operations, marketing — everyone played their part. And what I find most interesting is that I don't think it was the product most people expected from Revolut. But customers adopted it, and that says it all."

From solving travel to solving everyday life

The success of eSIM opened a bigger question. If customers valued accessing connectivity through the app when they travelled, what about at home?

"eSIM was a fantastic confirmation that people are genuinely interested in getting data through the Revolut app," Elyas explains.

In December 2025, Revolut Mobile was launched in the UK — giving customers access to calls, texts, and data roaming across Europe and the US, managed entirely from the app and activated in seconds.*

*Services provided by Gigs and 1Global. Revolut acts as an agent to facilitate access to these services.

The jump from a travel data feature to a fully managed mobile experience is more than just technical, it’s conceptual. Integrating phone numbers, number portability flows, and multi-market coverage into a single app required coordinating across partners, regulations, and infrastructure. The team's answer to each of those challenges was the same as it was for the eSIM:

• Understand the problem from scratch
• Build with as much simplicity as possible
• Never assume something can't be done just because nobody has done it before

For Elyas, this move says something important about where Revolut is heading. "It's a very strong statement that we're not just here for your day-to-day finances. We want to go further and become your ultimate lifestyle companion."

The profile of the people who built this

Behind each of these launches is a team that operates in a very specific way. At Revolut, a Product Owner needs to have a view on everything surrounding the product: design, data, engineering, marketing, operations.

On the engineering side, the profile is equally demanding. Someone who doesn't wait for the path to be laid out, who’s comfortable in unknown territory and understands that the best technical solution is almost always the simplest one. The Telecom team is a prime example of what happens when that profile meets a problem nobody has solved before.

What comes next

In just a few years, Revolut's Telecom team has built an experience that makes mobile connectivity feel as easy as managing your finances. The team did it with the certainty that if the right customer experience didn't exist, they would design it from scratch.

"This project perfectly reflects how we approach complex product challenges at Revolut," says Elyas."We simply solve them."