Alejandro Portillo Guerrero

Experienced iOS Engineer with 12+ years in designing, developing, and scaling high-performance applications. Skilled in Swift, SwiftUI, Objective-C, and cross-platform development, with proven ability to lead teams, integrate backend services, and deliver top-quality user experiences. Adept at working in both fast-paced startups and global enterprises, driving innovation, modular architecture, and test-driven development.

Passionate about building scalable, reliable products that reach millions of users.

GlobantiOS Software DesignerJune 2023 – Now FIFA+

Nov 2024 – Now

• Reduced crash rates by 80% through deep refactoring of legacy components and adoption of Swift async/await.
• Result: 99.9% app stability during global tournaments with millions of concurrent users.
• Led the integration of Airship push notifications, enabling delivery of personalized, event-driven content to fans worldwide and significantly improving user engagement during major competitions.

 Hablalo – Asteroid Technologies

June 2024 – Oct 2024

• Led the complete redesign of the iOS app with SwiftUI, delivering major improvements in performance, accessibility, and UX.
• Replaced Firebase deep linking with Branch, ensuring reliable navigation across 100k+ active sessions.
• Built a modular QR code system enabling business model pivots without reprinting costs, reducing operational overhead by 70%.

 Inditex IOP ProjectJun 2023 – Mar 2024 

• Owned iOS development of a new SaaS platform for enterprise workflow orchestration.
• Implemented a scalable architecture (SwiftUI + MVVM-C + DDD), laying foundations for multi-team development.
• Developed SDKs shared across Inditex teams, increasing velocity of new feature delivery.
• Achieved >90% automated test coverage (unit, snapshot, mutation, and E2E), improving release confidence and reducing regression bugs.

 Ola Invierte

Tech Lead

Sept 2021 – May 2023

• Owned the entire iOS lifecycle for a brokerage and crypto investment platform serving Spanish-speaking users across LATAM and the U.S.
• Delivered app from MVP to production with fully integrated KYC (Onfido), Vanguard Robo-Advisor, and real-time portfolio management.
• Designed scalable communication between mobile and backend services, enabling rapid expansion into new business lines (crypto + managed funds).
• Built internal tools including a Figma-to-React KYB generator, streamlining onboarding and cutting design–dev handoff time by 40%.

Orai AI Speech Coach & CopyCatTech Mobile Lead / Engineering Manager Jan 2018 – Sept 2021 

• Led development of AI-powered speech coach (iOS & Android), scaling from MVP to 300k+ downloads worldwide.
• Integrated Core ML for real-time speech analysis, enabling on-device feedback without cloud latency.
• Built a macOS widget with AI-driven insights, diversifying product offering.

 As Engineering Manager / Product Manager (Nov 2018 - Dec 2020):

• Directed a cross-functional team of 6 engineers, combining analytics, user research, and roadmap prioritization.
• Boosted product revenue by 50% in six months through iterative feature launches and growth experiments.
• Built a Figma plugin that auto-generated SwiftUI & React components, streamlining cross-platform development.
• Designed automated test pipelines for generated UI, improving reliability and reducing manual QA workload.

Doozy Inc.Tech LeadDec 2016 – Nov 2017

• Designed and led development of a real-time salon booking platform, integrating location-based services and dynamic scheduling.
• Fully developed iOS app (Swift, MVVM) and its widgets, while also managing backend integration (NodeJS).
• Improved platform adoption by designing highly scalable architecture for mobile + back-office.

William HillSenior iOS DeveloperAugust 2015– Nov 2016

• Migrated one of the industry’s leading betting apps to Swift, improving maintainability and performance.
• Built internal SDKs reused across multiple William Hill apps, standardizing functionality and reducing duplicated effort.
• Collaborated with cross-functional web teams, implementing Swift/Web bridging to integrate responsive features into native iOS apps.

BetVictoriOS DeveloperJuly 2013 – July 2015

• Led iOS development of BetVictor’s main app, scaling performance and reliability.
• Improved app store rating from 3★ to 4.5★ through UX improvements and stability enhancements.

CombustionProiOS DeveloperApril 2014 - Nov. 2014

• Development of app to prevent occupational hazards for Professional Associations of Labour Relations of Madrid

 Development of app to prevent occupational hazards for Professional Associations of Labour Relations of Madrid Voicle Inc.Junior iOS DeveloperSeptember 2012 – May 2013

• Development of their two main apps: Cliqs and Moodcup where we got over 50.000 downloads

Aug. 2012 – May 2013Exchange Student – Last year of Degree & Senior ThesisUniversity of Illinois at Urbana-Champaign, Illinois, United States of America 

• Developed an iOS application to extend the functionality of the Spanish Electronic Health Record (EHR) System, enabling smoother data access and improving overall healthcare provider efficiency.

Sept 2008 – May 20135-year Degree in Computer ScienceUniversidad de Granada, Granada, Spain