Muhammad is available for hire

Muhammad Khan

Verified Expert in Engineering

iOS Engineer and Developer

Vancouver, BC, Canada

Toptal member since March 12, 2026

Expertise

Coding Debugging Apple Pay Development POS System Security Computer Vision Code Review Machine Learning Prompt Engineering iOS Xcode Git

Bio

Muhammad is a senior iOS engineer with 12+ years of experience building high-performance platforms and SDKs for millions of global users. He's an expert in Swift, SwiftUI, and structured concurrency, with a focus on modularity and clean architecture. With a proven track record in video streaming, fintech, and secure authentication, Muhammad specializes in modernizing legacy systems, slashing crash rates, and leading end-to-end delivery of scalable, real-time mobile experiences.

Portfolio

Chronicle Creations Inc

Swift, SwiftUI, CI/CD Pipelines, Xcode, XCTest, XCUITest...

Screening Eagle Technologies

iOS, Swift, UIKit, SwiftUI, iOS SDK, XCTest, Mixpanel iOS SDK, Firebase, REST...

Marn Technologies

iOS, Swift, UIKit, SwiftUI, Tap payment, Mada, POS SDK, Epson SDK...

Experience

iOS - 12 years
Mobile App Security - 6 years
SDK Development - 6 years
SwiftUI - 6 years
Core ML - 4 years
VisionOS - 4 years
Generative Artificial Intelligence (GenAI) - 2 years
Artificial Intelligence (AI) - 2 years

Preferred Environment

iOS, Xcode, Swift, SwiftUI, AVFoundation, Core ML, VisionOS, ARKit, CI/CD Pipelines, Unit Testing

The most amazing...

...thing I'm building is https://sentinelden.com, an independent iOS security tool. OSS at https://github.com/sentinelden.

Work Experience

Lead iOS and Mobile App Security Engineer

2024 - 2026

Chronicle Creations Inc

Led the development of an AI-powered story platform (Swift 6 and SwiftUI) with 99.9% uptime across 100,000+ MAUs.
Improved API performance by 25% by refining concurrency, optimizing network layers, and introducing caching.
Reduced QA defects by 25% through improved onboarding, coding standards, and CI-driven automation.
Designed secure, modular authentication flows leveraging token-based protocols and SSL pinning.

Technologies: Swift, SwiftUI, CI/CD Pipelines, Xcode, XCTest, XCUITest, Object-oriented Programming (OOP), AWS Amplify, Firebase, Lottie-iOS, AVFoundation, GitHub Actions, Agile, Jira, MVVM-C, Testing, Social Media Login, iPadOS, Mobile, Mobile App Development, AppKit, Artificial Intelligence (AI), APIs, Payment APIs, PDF, Leadership, Mobile Development, User Interface (UI), Engineering, Generative Artificial Intelligence (GenAI), App Store, Google Analytics, Python, Python Script, Mobile App Security, SSL, Obfuscation, Reverse Engineering, Apple Pay, In-app Purchases, App Store Acceptance Process, TestFlight, App Store Connect, Supabase, Supabase Auth, Coding, Minimum Viable Product (MVP), Education Technology (Edtech), Learning, AI Integration, AI Model Integration, Apple Subscriptions, Subscriptions, AI-assisted Development, WatchOS, WatchOS UI, Apple HealthKit, IP Protection, Debugging, Instrumentation, IT Security, Scalability, Claude, Claude Code, Claude API, Claude Agent SDK, App Reviews, Code Review, Mobile Apps, Lottie, Loveable, Amazon Web Services (AWS), Prompt Engineering

Senior Software Engineer, iOS

2022 - 2024

Screening Eagle Technologies

Designed reusable, modular SDKs integrated across multiple product lines, reducing integration time by 25%.
Built real-time data and visualization features using WebSockets, Combine, and Charts for cross-platform environments.
Migrated legacy Objective-C modules to Swift and SwiftUI, reducing technical debt and improving maintainability.
Led an automated testing strategy, significantly increasing release stability for a multi-team organization.

Technologies: iOS, Swift, UIKit, SwiftUI, iOS SDK, XCTest, Mixpanel iOS SDK, Firebase, REST, Apple Pay, LiDAR, ARKit, PSPDFKit, GitLab CI/CD, Core ML, Jira, Agile, MVVM-C, Clean Architecture, XCUITest, CoreLocation, MapKit, Google+ iOS SDK, Social Media Login, OAuth 2, Mobile, Mobile App Development, AppKit, Artificial Intelligence (AI), APIs, User Interface (UI), Mobile Development, Leadership, Engineering, Mixpanel, Reverse Engineering, SSL, Obfuscation, Mobile App Security, SDK Security, SDKs, App Store, App Store Acceptance Process, TestFlight, App Store Connect, Google Maps, Apple Maps, Coding, C++, App Reviews, Code Review, Mobile Apps

Senior iOS Engineer

2021 - 2022

Marn Technologies

Built modular frameworks for hardware integrations, including scanners, printers, and terminals, improving developer velocity.
Engineered low-latency local network communication protocols, achieving over 99% uptime in high-volume environments.
Improved system reliability by introducing analytics-driven enhancements and performance instrumentation.
Collaborated with product, QA, and back-end teams to streamline workflows and shorten release cycles.

Technologies: iOS, Swift, UIKit, SwiftUI, Tap payment, Mada, POS SDK, Epson SDK, Firebase iOS SDK, REST, Payment APIs, Agile, Jira, Model View ViewModel (MVVM), Unit Testing, Testing, CoreLocation, Google Maps SDK, Mobile, Mobile App Development, AppKit, APIs, Apple Pay, MacOS, App Store, App Store Acceptance Process, TestFlight, App Store Connect, Flutter, Dart, JavaScript, React Native, Node.js, Coding, Bluetooth Beacons, Internet of Things (IoT), App Reviews, Code Review, Stripe API, Mobile Apps, Lottie, Amazon Web Services (AWS)

Senior iOS Engineer, eCommerce and Loyalty

2019 - 2021

Cooperative Computing

Delivered core iOS features used by millions of global users across multiple production apps.
Reduced checkout flow failures by 12% by optimizing critical paths and simplifying UI interactions.
Improved production reliability by 15% by driving monitoring, structured logging, and automated incident workflows.
Accelerated release velocity 25% through CI/CD improvements and engineering process refinement.

Technologies: iOS, Swift, UIKit, OpenCV, Optical Character Recognition (OCR), Amplitude, REST, AVFoundation, Core Graphics, Core Animation, GitHub, Agile, OAuth, Azure, Model View ViewModel (MVVM), Unit Testing, Mobile, Mobile App Development, AppKit, APIs, Payment APIs, App Store, App Store Acceptance Process, TestFlight, App Store Connect, Coding, App Reviews, Code Review, Mobile Apps, Lottie, Amazon Web Services (AWS)

Senior iOS Engineer

2018 - 2019

Invision Solutions

Developed two applications single-handedly. Improved app reliability through faster development cycles and introduced unit testing for junior developers, reducing defects by 40%.
Performed development and handled management of iOS mobile apps.
Evaluated ongoing projects technically and performed code previews.
Managed projects and defined requirements, scoping, and goals. Handled version control using tools like Git.

Technologies: iOS, Swift, RxSwift, UIKit, MapKit, Google+ Authentication, Firebase iOS SDK, Unit Testing, Git, Bitbucket, App Store, Objective-C, App Store Acceptance Process, TestFlight, App Store Connect, Coding, App Reviews, Code Review, Mobile Apps, Lottie, Kingfisher, Amazon Web Services (AWS)

Senior iOS Engineer

2017 - 2018

Lutebox

Handled mobile app development. Team management was my core responsibility.
Designed public-facing Swift SDKs with documentation and versioning, reducing support requests by 30% and speeding partner onboarding.
Achieved 90% client satisfaction with initial product mockups and delivered 4 major updates on time.
Coordinated feature rollouts with less than 1% downtime.

Technologies: iOS, iOS SDK, Firebase iOS SDK, Google Cloud, REST, AVFoundation, Google Maps SDK, Google Location API, Google+ Authentication, Apple Pay, App Store, Objective-C, App Store Acceptance Process, TestFlight, App Store Connect, Mobile Apps, Lottie, Kingfisher, Amazon Web Services (AWS)

Experience

Dreambook Kids

https://dreambook.kids/

Dreambook transforms complex technologies into accessible and child-friendly features that empower kids to express their creativity with ease, allowing children to focus on imagination and storytelling.

Screening Eagle Inspect

https://apps.apple.com/ca/app/screening-eagle-inspect/id1520348552

Screening Eagle Inspect is the world's first intelligent and intuitive solution specifically developed for managing inspection data and workflows. A seamless experience makes inspections efficient, traceable, collaborative, and intelligent, with actionable dashboards and deep dynamic reporting.

Pampers Rewards

https://apps.apple.com/us/app/pampers-rewards/id1224627026

I built a high-performing iOS app in Swift and SwiftUI that enables users to scan diaper and wipes QR codes to earn rewards. I integrated real-time rewards tracking, personalized parenting content, milestone tools, and a seamless redemption flow for coupons, gift cards, and charitable donations. I also enhanced user engagement with intuitive UI and reliable back-end syncing for millions of active users.

Marn POS

https://apps.apple.com/us/app/marn/id1495693049

I developed native iOS features in Swift for managing employee profiles, inventory tracking, and product catalog management within a cloud-based POS solution. I also designed intuitive interfaces and implemented seamless role-based access control, streamlining operations for merchants in retail and restaurant settings.

Garage POS

https://apps.apple.com/sa/app/garage-pos/id1454372626

I developed a secure, iPad-centric POS system in Swift tailored for automotive service businesses. This system includes features such as vehicle profile management based on license plate and VIN, real-time inventory and sales tracking, and support for multiple payment methods. I integrated Epson and Zebra printers for seamless receipt and report generation. Additionally, the system enables comprehensive data capture, including checklists, multimedia notes, and X/Z reports, significantly enhancing operational efficiency and customer satisfaction.

SentinelSDK: iOS Runtime Defense Framework

https://sentinelden.com/sdk/sentinel

A hardened iOS runtime-defense framework featuring five concurrent scanners, jailbreak filesystem heuristics (covering rootless overlays like /var/jb/), Mach-O integrity checks (LC_ENCRYPTION_INFO_64.cryptid for re-signed binaries), loaded dylib inspection (Frida and ElleKit injection regardless of agent rename), kernel-level debugger detection via sysctl(KERN_PROC, ...), and screen-capture detection, all aggregated into a typed SecurityReport. The framework also includes App Attest integration for server-side trust. Built using public iOS APIs only, it uses PrivacyInfo.xcprivacy to declare required-reason categories at the precise reason-code level (3B52.1, 35F9.1). Designed for iOS 17+, it ships as a code-signed .xcframework with a hardware-uptime-anchored license clock.

CryptoShield SDK: iOS Networking Defense

https://sentinelden.com/sdk/cryptoshield

An iOS networking-defense SDK that hardens the URLSession path against corporate MITM proxies, in-process tampering, and certificate-trust manipulation. It implements three-pin SPKI validation across the full SecTrust chain, along with payload encryption above TLS using ephemeral P-256 ECDH against an embedded server public key, HKDF-SHA256 key derivation, and AES-256-GCM sealing with AAD-bound counters, millisecond timestamps, and per-route context tags. The SDK also ships with server-side decryption reference implementations in Node.js, Python, and Go, plus pinned WebSocket support with automatic rekeying. It composes with SentinelSDK so payloads refuse to seal on compromised devices.

AgenticGuard SDK: On-device LLM Agent Sandbox

https://sentinelden.com/sdk/agenticguard

An iOS sandbox for on-device LLM agents using Apple Foundation Models, MLX, Core ML, and custom runtimes. It defends against three classes of agent failure: prompt injection through structurally separated system, user, and retrieved channels with a heuristic-plus-small-model classifier; capability escalation through a typed tool registry with schema validation, per-tool quotas, and OS-level confirmation gates; and data exfiltration through a typed AgentNetworkPolicy with domain allowlists and shape constraints. The platform also includes a hash-chained audit trail with entries signed by a Secure Enclave-backed P-256 key, verifiable off-device through a documented 81-byte canonical layout. It uses a fail-closed verify(intent:) approach, with internal errors materializing as .deny.

EnclaveVault SDK: Apple Secure Enclave Wrapper

https://sentinelden.com/sdk/enclavevault

A typed Swift wrapper around Apple's Secure Enclave that prevents the failure mode where forgetting kSecAttrTokenIDSecureEnclave silently downgrades to a software keychain key, an invisible-by-default bug found in many production iOS apps. It implements BiometricPolicy as code, including invalidation (biometryCurrentSet vs. biometryAny), passcode fallback (.allow vs. .deny), retry behavior, and prompt strings, each exposed as a typed argument rather than a magic flag. The framework also requires an explicit FallbackPolicy argument, so host applications must choose between .requireHardware and .keychainFallback. The CI-grade attestEnclaveResidency() primitive uses SecKeyCopyAttributes to verify that the key was actually stored in the Secure Enclave hardware.

Sentinel Studio: macOS App for iOS Binary Audits

https://sentinelden.com/studio

A notarized macOS application for security auditing iOS binaries (.ipa, .xcframework, and .xcarchive). The rule-pack engine includes built-in coverage for OWASP MASVS, iOS privacy manifests, crypto hygiene, network policy, and anti-tampering patterns, with support for custom packs via YAML. An attack-chain engine runs dynamic instrumentation scenarios including MITM proxy substitution, re-encoded IPA replay, Frida injection probes, and screen-recording detection. The platform also supports signed report exports in PDF, JSON, and HTML formats for compliance and audit teams. Distributed with a signed Developer ID, Apple notarization, and stapling, the update manifest is delivered as an ECDSA-P256-signed JSON envelope.

Education

2008 - 2010

Master's Degree in English and Computer Programming

SALU Pakistan - Pakistan

2006 - 2008

Bachelor's Degree in Arts and Computer Programming

SALU Pakistan - Pakistan

Certifications

DECEMBER 2011 - PRESENT

Mobile App Software Development Bootcamp

SSUET Karachi, Pakistan

Skills

Libraries/APIs

AWS Amplify, Lottie-iOS, Mixpanel iOS SDK, Firebase iOS SDK, OpenCV, Core Graphics, Core Animation, Google Maps SDK, Google+ iOS SDK, RxSwift, Google Location API, Google Maps, Apple Maps, WebRTC, Apple Subscriptions, Google Maps API, Stripe, Claude API, Stripe API, Kingfisher, React, Node.js

Tools

Xcode, GitLab CI/CD, GitHub, Jira, CoreLocation, Git, Bitbucket, Google Analytics, TestFlight, Apple HealthKit, Claude, Claude Code, Claude Agent SDK, SAP SDK, SAP UI5, SAP Fiori, Esri

Languages

Swift, Python, Python Script, Objective-C, C++, TypeScript, Dart, JavaScript, Java

Frameworks

SwiftUI, Core ML, ARKit, XCTest, XCUITest, UIKit, iOS SDK, MapKit, OAuth 2, AppKit, API Framework, Apple CryptoKit, Core Motion, Tailwind CSS, Flutter, React Native

Paradigms

Unit Testing, Object-oriented Programming (OOP), Mobile App Design, REST, Agile, Clean Architecture, Model View ViewModel (MVVM), Testing, Mobile Development, Code Refactoring, Foundation Models

Platforms

iOS, VisionOS, Firebase, Azure, Mobile, MacOS, Mixpanel, WatchOS, Amazon Web Services (AWS), Android, SAP Mobile

Storage

SQLite, Google Cloud

Other

AVFoundation, CI/CD Pipelines, IT Troubleshooting, Mobile App Development, Apple Pay, LiDAR, PSPDFKit, GitHub Actions, Tap payment, Mada, POS SDK, Epson SDK, Payment APIs, Optical Character Recognition (OCR), Amplitude, OAuth, MVVM-C, Social Media Login, iPadOS, Google+ Authentication, APIs, PDF, Bluetooth Beacons, WebSockets, Tap Payments, POS, Leadership, User Interface (UI), Engineering, Generative Artificial Intelligence (GenAI), App Store, Reverse Engineering, SSL, Obfuscation, Mobile App Security, SDK Security, In-app Purchases, SDKs, App Store Acceptance Process, App Store Connect, GPS Integration, GPS, RoomPlan, Coding, Push Notifications, Messaging, Internet of Things (IoT), Computer Vision, Machine Learning, Software Architecture, Minimum Viable Product (MVP), Education Technology (Edtech), Learning, AI Integration, AI Model Integration, Subscriptions, API Integration, System Integration, Performance Optimization, AI-assisted Development, VisionKit, Frameworks, Security, Mach-O, App Attest, DeviceCheck, Jailbreak Detection, Frida Detection, Runtime Defense, SDK Development, P-256 ECDSA, TLS Pinning, SPKI Hashing, AES-GCM, ECDH P-256, HMAC Key Derivation function (HKDF), Network Security, MITM Defense, Replay Protection, Cryptographic Protocol Design, LLM Security, Prompt Injection Defense, On-device AI, MLX, ECDSA-P256, Hash Chains, Audit Logging, Sandboxing, SecKey, SecAccessControl, LocalAuthentication, FaceID, TouchID, Biometric Authentication, Key Storage, LAContext, Hardware-backed Crypto, macOS Development, iOS Security Audit, Mach-O Analysis, Notary, Code Signing, Binary Analysis, OWASP MASVS, Static Analysis, Dynamic Instrumentation, DMG Distribution, Tracking, WatchOS UI, IP Protection, Debugging, Instrumentation, IT Security, Scalability, App Reviews, Code Review, Vulnerability Assessment, Auditing, Audits, Mobile Apps, Lottie, Loveable, Prompt Engineering, Artificial Intelligence (AI), Yapdatabase, Supabase, Supabase Auth, SAP, MDK, SSAM, AI Pipeline

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