Juegos ONCE

Company

ZEAL Network SE is a publicly traded online lottery and digital gaming group headquartered in Hamburg, Germany. Founded in 1999 (originally as Tipp24 SE), ZEAL operates leading lottery brokerage platforms such as Lotto24 and Tipp24, offering state-licensed lottery products and other gaming services across Europe.

With a strong focus on secure, regulated digital experiences, ZEAL also drives innovation through segments like ZEAL Iberia, ZEAL Instant Games, and ZEAL Ventures, and maintains strategic partnerships — including with ONCE in Spain. The company serves millions of active customers through its technology-driven lottery offerings.

Project

Juegos ONCE (iOS)

At ZEAL Network SE, I worked on the Juegos ONCE iOS application, the official mobile app of ONCE in Spain. This is a high-traffic, production-critical product used daily by a large and diverse user base, where reliability, accessibility, and long-term maintainability are essential.

As part of the iOS team, my work focused on continuous evolution of the app, delivering new features while ensuring stability and high quality standards in a mature codebase.

Key Responsibilities

• Maintenance and continuous evolution of a large-scale iOS application in production.
• Development of new features within an established and mature codebase.
• Progressive migration from UIKit to SwiftUI, ensuring stability and smooth adoption.
• Clean Architecture adoption and improvements, increasing modularity, scalability, and testability.
• Strong focus on iOS Accessibility, improving usability for users relying on assistive technologies such as VoiceOver.
• Refactoring and modernization of legacy code, while maintaining high quality standards.

Highlights

• Accessibility-first mindset: contributed to improving the user experience in an app where accessibility is a key pillar, aligned with ONCE’s strong commitment to inclusive digital products in Spain.
• Architecture-driven development: applied Clean Architecture principles to reduce coupling, improve code clarity, and enable safer long-term evolution of the product.
• Modernization without disruption: helped evolve the app by introducing SwiftUI progressively, avoiding risky “big rewrites” and keeping the product stable in production.