I began by running sessions with cross-functional teams to develop a genuine working understanding of CallKit technology and the material differences between iOS and Android that would shape the experience structurally. I mapped the existing contact and app architecture to understand exactly where SafeCall would need to sit -and what the transitions between systems would feel like to a customer under stress.

Three things became clear from this research:

The active call screen was everything. If a customer hesitated or doubted what they were looking at in that moment, the feature had already failed.

The seams between systems were the biggest usability risk. Native-to-web transitions, permission logic, and multi-device behaviour all had the potential to introduce exactly the kind of confusion scammers exploit. Everyone one of those seams needed a design solution.

Trust and clarity couldn't be assumed. They had to be designed, deliberately, at every step.

This wasn't background context. It became the foundation every subsequent decision was built on.

I established three principles to govern every decision across the UX and Ul:

• Trust is established in the first second - the active call screen was the centrepiece of the entire experience. Westpac name, call context and Optus verification had to land immediately and unambiguously. Hierarchy, not decoration, was the design tool.

• Complexity belongs behind the interface, not in it - SafeCall involved backend integrations across two organisations, platform-specific CallKit behaviour, OTP flows, and layered permission logic. None of that belonged in front of the customer. Every decision was made to absorb the complexity, not expose.

• Security cannot create the feelings it exists to prevent - scammers exploit confusion, urgency and overwhelm. The legitimate call experience had to be the opposite: calm, sequential, and unambiguous at every step.

Using the customer's existing OTP number was the right security decision but it created a jarring native-to-web transition mid-flow. I resolved this through carefully positioned native load screens, explicit user feedback states and a forced return to the native flow once the update was complete. The seam was still there. The customer wouldn't feel it.on text goes here

Calls would only ring on one registered device. The deliberate reason: the confusion of a call arriving across multiple devices is precisely the kind of disorientation scammers manufacture. A single-device experience eliminated that entirely from registration through to the active call.

iOS required microphone and notification permissions. Android required phone, microphone, full screen alerts and notifications. I had to balance transparency, explaining why each permission was needed - against legal and compliance requirements, friction minimisation and the business need to drive SafeCall adoption. I landed on requesting permissions once at first interaction, then only again at the next relevant touchpoint. Maximum uptake, minimum overwhelm.