Senior iOS Engineer · Freelance

I build native iOS products and help mobile teams deliver with clarity.

Senior iOS engineer, mobile architect and occasional interim engineering manager with 10+ years across travel, commerce and consumer apps. I work across hands-on Swift delivery, architecture, roadmap execution and stakeholder alignment.

Discuss a missionView experience

Available for iOS consulting, architecture audits, Swift / SwiftUI delivery and interim leadership engagements.

How I work

Architecture, delivery and product impact — not just code.

I work best where mobile quality matters: high-traffic apps, critical flows, complex integrations and teams that need a senior engineer who can own both technical depth and delivery clarity.

My approach is pragmatic: understand the product goal, simplify the architecture, create a clear delivery path and ship in small, reliable increments — increasingly with AI-assisted and agentic workflows where they genuinely help.

I have contributed to Trainline's international growth, LALALAB's checkout and product creation flows, and earlier iOS / web products involving real-time communication and IoT dashboards.

Product first

Technical decisions are anchored in user experience, business impact and measurable outcomes.

Architecture that ships

I favor modular, testable systems that reduce risk and accelerate future delivery.

Senior communication

I keep stakeholders aligned on scope, trade-offs, risks and priorities.

Team leverage

I mentor, document and share practices so improvements persist after the mission.

Freelance services

Senior iOS support for teams that need reliable delivery.

Whether you need a hands-on senior engineer, a mobile architecture review or temporary leadership, I can join your team and help move the product forward.

iOS Architecture Audit

Review your current iOS architecture, modularization, dependencies, testing strategy, CI/CD and release risks, then deliver a prioritized improvement roadmap.

Best for

Scaling teamsLegacy modernizationSlow feature deliveryUnstable releases

Deliverables

  • Architecture assessment
  • Risk map
  • Modernization roadmap
  • Quick wins
  • Team recommendations

Hands-on Swift / SwiftUI Delivery

Design and build critical native iOS features with clean implementation, test coverage, analytics hooks and production-ready delivery — using AI-assisted and agentic workflows where they help without compromising quality.

Best for

Feature accelerationCritical product roadmapComplex mobile flowsSenior delivery ownership

Deliverables

  • Feature implementation
  • Code reviews
  • Tests
  • AI-assisted workflows
  • Documentation
  • Release support

Interim Tech Lead / Engineering Manager

Support a mobile team through roadmap planning, stakeholder alignment, delivery tracking, technical trade-offs and team rituals while staying close to implementation.

Best for

Temporary leadership gapDelivery resetRoadmap clarificationCross-functional alignment

Deliverables

  • Roadmap structure
  • Delivery plan
  • Stakeholder updates
  • Risk management
  • Team rituals
  • AI workflow adoption

→ Served as interim Engineering Manager for a Trainline team of 6 engineers.

Growth, Checkout and Payments

Improve high-leverage journeys such as onboarding, checkout, payment, product creation and conversion funnels through reliable engineering and experimentation.

Best for

Conversion optimizationPayment reliabilityCheckout redesignExperimentation

Deliverables

  • Flow audit
  • Implementation
  • Instrumentation
  • A/B test support
  • Release monitoring

→ Redesigned LALALAB checkout, increasing conversion by 28%.

Quality, CI/CD and Observability

Make iOS delivery safer and faster with test strategy, build automation, release processes, monitoring and performance feedback loops — including AI-assisted code review and agentic workflows in CI where they add real signal.

Best for

Slow releasesRegression riskLow confidence deploymentsProduction visibility

Deliverables

  • CI/CD improvements
  • Fastlane / TeamCity setup
  • AI-assisted code review
  • Observability recommendations
  • Testing plan
  • Release checklist

Engagement models

Flexible ways to work together, scaled to your timeline and the outcome that matters most.

1-3 weeks

Architecture Sprint

Teams that need a clear technical diagnosis and action plan before investing in a larger rebuild or roadmap.

1-6 months

Delivery Mission

Teams needing a senior iOS engineer to own critical features, unblock delivery and improve quality while shipping.

2-6 months

Interim Mobile Lead

Teams with a temporary leadership gap, unclear roadmap or high coordination load.

Monthly retainer

Continuous Advisory

Founders, CTOs and mobile teams that need recurring senior input on architecture, hiring, roadmap and quality.

Professional journey

From senior iOS delivery to roadmap and team leadership.

  1. Senior iOS Engineer & Interim Engineering Manager

    Trainline
    2022 — NowParis, France

    Building iOS journeys for a travel platform serving 150M+ travelers and around 1M+ monthly active users, with a focus on international growth, scalable architecture and reliable product delivery.

    • Served as interim Engineering Manager for 6 engineers, leading roadmap creation, priority clarification, stakeholder exchanges and delivery.
    • Revamped critical flows with product, design and data partners to improve retention and average basket value.
    • Automated support for new suppliers by 80%, improving delivery scalability.
    • Introduced agentic AI development workflows into the iOS stack to support faster delivery and consistent code quality.
    • Contributed to iOS community initiatives to improve knowledge sharing and engineering standards.
    • Worked with hexagonal architecture, SwiftUI, Firebase, Tuist, TeamCity, A/B testing and New Relic.
    SwiftSwiftUIHexagonal ArchitectureFirebaseTuistTeamCityA/B TestingNew RelicAI-assisted developmentAgentic workflowsRoadmapStakeholder ManagementEngineering Leadership

  2. iOS Engineer

    LALALAB
    2020 — 2022Paris, France

    Supported a consumer photo-printing app used by 4M customers and around 500k monthly active users, with a focus on scalable architecture, checkout and product creation.

    • Redesigned checkout and payment flows, increasing conversion by 28%.
    • Implemented a reusable, pixel-perfect product creation system that reduced QA cycles and improved support for new products.
    • Delivered Sign in with Apple integration supporting 40% of new user signups.
    • Used MVVM, Firebase, Fastlane and cross-team collaboration with product and design.
    SwiftMVVMCheckoutPaymentsSIWAFirebaseFastlanePixel-perfect UI

  3. Software Engineer

    Frianbiz
    2019 — 2020Paris, France

    Developed and maintained iOS and web projects, including real-time features and dashboards.

    • Architected real-time Socket.IO communication for a live game chat system.
    • Implemented a custom dashboard for distributed IoT devices.
    • Worked with VIPER, MVP, RealmDB, unit testing, Angular and PHP.
    iOSVIPERSocket.IORealmDBUnit TestingAngularPHP
Use cases

The kind of work I can own end to end.

Scaling new supplier support at Trainline

Context
International travel growth required supporting new suppliers with less manual work and more predictable delivery.
Action
Helped modernize iOS integration paths, improve architecture and automate supplier support workflows.

Result · 80% automation improvement for new supplier support.

Interim leadership for a 6-engineer mobile team

Context
The team needed delivery structure, clearer priorities and stakeholder alignment while continuing to ship.
Action
Led roadmap creation, coordinated stakeholders, clarified scope and managed delivery rituals for 6 engineers.

Result · Clearer priorities and steadier delivery for the team.

Checkout redesign and payment reliability at LALALAB

Context
Checkout was a high-leverage conversion path for a consumer photo-printing app.
Action
Redesigned checkout and payment flows with strong attention to user confidence, reliability and pixel-perfect implementation.

Result · +28% checkout conversion.

Reusable product creation system

Context
LALALAB needed to support a diverse product catalog without slowing QA and delivery cycles.
Action
Implemented a reusable, pixel-perfect product creation system.

Result · Reduced QA cycles and improved new product support.

Skills & expertise

Senior iOS depth with enough breadth to unblock the full product path.

Native iOS

SwiftSwiftUIUIKitObjective-CXcodeXCTestSwift ConcurrencyCore frameworks

Architecture

Hexagonal ArchitectureClean ArchitectureMVVMVIPERMVPModularizationDependency InjectionScalable systems

Product & Growth

A/B TestingCheckoutPayment flowsRetentionAverage basket valueAnalyticsConversion optimizationUser-centric delivery

Delivery & Quality

CI/CDFastlaneTeamCityTuistFirebaseNew RelicTestingRelease automationObservability

Leadership

Roadmap creationStakeholder alignmentInterim engineering managementMentoringCode reviewAgile deliveryKnowledge sharing

T-shaped capabilities

AndroidRubyLaravelAngularREST APIsSocket.IORealmDBFigmaZeplinPhotoshop

AI-Enhanced Engineering

Agentic developmentAI-assisted developmentAgent orchestrationLLM toolingAI code reviewContext engineering (RAG)MCP (Model Context Protocol)Evals & guardrails
Knowledge sharing

Writing and technical curiosity.

Selected articles from earlier engineering work and experiments.

Apr 24, 2020Medium

Unit Testing in Xcode: From 0 to 1

XcodeUnit TestingTestingSwift
Sep 18, 2019Medium

Pixology: The New Frianbiz Adventure

iOSPixologyGameCinemaSocket.IO
Jul 10, 2019Medium

AI Unity Game for Dummies

Game DevelopmentUnityAIFinite State Machine
Foundation

Engineering foundation in computer science.

Engineering Degree — Computer Science

2015 — 2018

Hassania School of Public Works (EHTP)

Casablanca, Morocco

Preparatory Classes — Mathematics & Physics

2013 — 2015

Ibn Taymiya

Marrakech, Morocco

Scientific Baccalaureate

2012 — 2013

Wahat Ezzaytoun

Marrakech, Morocco

Languages

Working across European teams.

English

Fluent

French

Bilingual

Arabic

Native

German

Beginner

Get in touch

Need a senior iOS engineer who can own delivery, architecture and team alignment?

Tell me about your product, your current mobile challenge, team context and timeline. I will reply with the best way I can help — from a focused audit to hands-on delivery or interim leadership.

Email MohamedConnect on LinkedIn

A good first message answers

  • 01What iOS product or feature needs help?
  • 02Is the mission mostly architecture, delivery, leadership or a mix?
  • 03What is the team size and current mobile stack?
  • 04What deadline or business outcome matters most?

Find me online

LinkedInGitHubMedium

© 2026 Mohamed Derkaoui — Senior iOS Engineer · Paris