How Belfius gave every customer borderless mobile data, with zero integration

In June 2025, Belfius became the first Belgian bank to offer free borderless mobile data to all of their customers. It took zero engineering effort. There was no API integration. No carrier negotiation. No mobile app changes.

This case study covers what they did, why it worked, and why most companies overcomplicate "adding connectivity to your product."

The problem

Belfius's customers travel. Their banking app is their primary tool abroad: balances, transfers, card controls, fraud alerts. When customers travel internationally, several things happen:

1. International roaming costs deter them from using mobile data

2. Public WiFi raises security concerns for banking

3. Customers buy local SIM cards, but those don't keep their primary number

4. Two-factor authentication SMS messages depend on the customer being reachable

The combined effect: a banking app that's most needed when traveling is least used. Belfius wanted to fix this.

The solution

Belfius added a single link to their banking interface: "Get free worldwide data." The link points to a Firsty-hosted webapp branded for Belfius. Customers click the link, authenticate, and get a free eSIM with global coverage.

That's it. The entire integration was adding one link.

The webapp handles everything:

• Authentication (delegated via OAuth)

• Device compatibility check

• eSIM provisioning

• QR code display and installation instructions

• Customer support flows

Belfius did not write a single line of code. They did not integrate the API. They did not run their own provisioning infrastructure. They added a link.

Why this is more clever than it sounds

When we talk to fintechs and banks about embedding connectivity, the first question is always "how complex is the integration?" The answer they expect is "weeks of engineering work."

For complex use cases (native in-app eSIM provisioning, custom flows, tight UI integration), that's true. For the 80% of use cases that just want to offer free data to customers, it's wildly overengineered.

The webapp approach trades some control for radically less effort:

Belfius chose webapp because their goal was clear: every customer should have access to free roaming data. They didn't need it to be deeply embedded in the banking experience. A link in the menu is enough.

What customers see

From the customer's perspective:

1. Open Belfius app or web banking

2. Tap "Get free worldwide data"

3. Customer is redirected to a Firsty-hosted webapp branded as Belfius

4. Authenticate (single sign-on via Belfius)

5. Confirm their device is eSIM-compatible

6. Receive a QR code and installation instructions

7. Install eSIM on phone

The whole flow takes about 2 minutes. The customer never knows they left Belfius's product (the webapp is co-branded), and they never realize Firsty exists in the chain. From their perspective, Belfius gave them free roaming.

What Belfius gets

Beyond the customer-facing benefit, the integration creates real business value:

Customer retention: free roaming is a strong loyalty signal. Customers tell their friends. Word-of-mouth growth was significant after launch.

App engagement abroad: customers actually use the banking app while traveling now. The data shows clear uplift in international transaction monitoring.

Differentiation: Belfius is the only Belgian bank offering this. Competitors have to either copy or watch customers prefer Belfius for international features.

Zero ongoing cost to Belfius IT: there's no integration to maintain, no carrier relationships to manage, no infrastructure to monitor.

What we (Firsty) handle

Firsty operates the webapp, the connectivity, and the customer support infrastructure. We handle:

• Tier-1 carrier relationships and network access

• Real-time eSIM provisioning

• Multi-IMSI failover across regions

• Customer device compatibility logic

• QR code generation and delivery

• Installation support documentation

Belfius doesn't touch any of this. They handle their customer relationship; we handle the connectivity layer.

When the webapp approach is right

The Belfius pattern works when:

• You want to offer connectivity to your customers without becoming a connectivity expert

• A co-branded experience is acceptable (vs fully native UI)

• You don't need deep integration with your product's data

• You want to launch in days, not months

• You don't have engineering resources to spare

The webapp approach is wrong when:

• Connectivity is central to your product (then you want full API control)

• You need to embed eSIM provisioning inside a specific flow in your app

• You want to track usage data inside your own analytics

• You're a connectivity-first product (travel eSIM app, IoT platform)

For pure "add free data to my customers' experience" use cases, webapp is the right answer 90% of the time.

What's next for Belfius

Belfius is exploring deeper Firsty integrations:

• Higher-tier data plans for premium customers

• Adding the same offering to business banking customers

• Integration with their travel insurance product

But these are evolutions, not corrections. The webapp approach delivered the core value within weeks of decision to launch.

Could this work for your product?

If you're a regulated entity (bank, fintech, insurance company) thinking about adding connectivity, the Belfius pattern is the simplest possible integration. The requirements:

• A place in your product to add a link (menu item, settings page, marketing email)

• Single sign-on capability (so customers don't need to re-authenticate)

• That's it

The webapp is fully white-label. Your logo, your colors, your domain if you want it. The customer experience is yours.

If you're considering this, contact us. We can show you a live demo of how the Belfius webapp works and walk through how to set up a similar flow for your customers.