Banco Santander

The challenge

The Core team behind OneApp Europe needed to scale its iOS development capacity to handle the functional evolution of the app, technical maintenance, and the resolution of long-standing bugs that had been blocking releases for some time. This critical workload required a senior iOS profile able to onboard quickly, understand the existing architecture, and deliver value from the first sprint.

The solution

AtalayaSoft assigned Francisco José García Navarro as an external senior iOS engineer embedded in the OneApp Europe Core team, working fully remote for more than two years. His role covered three parallel fronts:

1. Core component development on OneApp Europe

As senior iOS reinforcement on the Core team, Francisco developed components used by Banco Santander apps in Spain, Portugal, the UK and Poland. The scope included:

• Resolving functional bugs and incidents in the application.
• Developing new features and new screens.
• Executing unit tests and preparing service calls with their corresponding data layer integration.
• Supporting and mentoring more junior team members.

2. Cross-cutting work on Santander Technology & Operations (T&O)

In parallel, Francisco supported the T&O area on tasks affecting multiple internal bank apps:

• Development of reusable libraries across projects.
• Proof of Concept (PoC) development to validate solutions before rolling them out to other teams.
• Maintenance of several internal apps for bank employees: bug fixes, iOS-version updates and new features.
• Store management: certificates, app signing and re-signing, publishing to TestFlight and AppCenter.
• CI and CD deployment for various GitHub projects, including Santander Spain.
• Technical support for other teams across the bank.

3. iOS accessibility improvements on OneApp Europe

Following internal accessibility audits run by the bank, Francisco applied native iOS improvements to the app: review of VoiceOver labels and traits, semantics adjustments for screen readers, focus order fixes on critical flows, and Dynamic Type support for accessible font sizes. This is exactly the kind of work the European Accessibility Act (EAA) now mandates for financial-sector apps.

Featured technical achievements

Long-standing bug fix using Charles

One of the apps had a persistent bug affecting the update process that had resisted previous attempts to fix it. The team had no access to the vendor's documentation, so Francisco solved it through reverse engineering with Charles Proxy (an HTTP proxy that allows inspection of network traffic between the app and the backend in real time), reconstructing the undocumented contract and identifying where the client–server sync was breaking down.

MSAL library for corporate authentication

Several bank teams needed to integrate the Microsoft Authentication Library (MSAL) in their iOS apps, but each was doing so separately. Francisco designed and built an internal reusable library that centralized that integration, distributed it via Swift Package Manager (Apple's official dependency manager for Swift projects), and trained the consumer teams. Result: reduced code duplication and accelerated onboarding of MSAL in future projects.