Open to opportunities

William User

@williamuser6

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Senior Mobile Engineer building reliable cross-platform iOS and Android apps with scalable backends.

United States

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What I'm looking for

I am seeking senior mobile engineering roles building cross-platform and native apps with strong engineering practices, CI/CD, and collaborative teams.

I am a Senior Mobile Engineer with over 11 years of experience building iOS and Android applications across healthcare, education, transportation, social media, and consumer tech.

I specialize in cross-platform and native mobile development using React Native, Flutter, Kotlin, Swift, Objective-C and Java, and connect apps to backends using TypeScript, Go, GraphQL and serverless architectures on AWS, Firebase and Google Cloud.

I have led projects end-to-end: publishing apps to the App Store and Google Play, improving CI/CD pipelines with Fastlane and Python scripting, and raising user satisfaction through analytics-driven improvements and robust automated testing.

I focus on creating fast, reliable, and user-friendly mobile solutions, improving performance and stability, reducing crash rates, and accelerating time-to-market while collaborating effectively with cross-functional teams.

Experience

Work history, roles, and key accomplishments

Senior Mobile Developer

Baycare

Mar 2022 - Sep 2025 (3 years 6 months)

Built cross-platform doctor appointment and decision-support apps using React Native and native iOS/Android, reducing post-launch issues by 40% and cutting deployment time by 50% via CI/CD automation.

React Native Kotlin Swift GraphQL Firebase Fastlane Expo RESTful APIs

Mobile Application Developer

Zubie

Nov 2017 - Feb 2022 (4 years 3 months)

Led a full rebuild of a driver-facing app with a single Flutter codebase, cutting development time by 40% and crash rates by 30% while increasing user satisfaction and subscriptions.

Flutter AWS Lambda API Gateway DynamoDB Firebase Stripe GraphQL TestFlight

Mobile Developer

OpenLogix

Aug 2014 - Sep 2017 (3 years 1 month)

Developed instant messaging apps in Kotlin and Swift, added Signal Protocol end-to-end encryption and migrated REST to GraphQL, reducing API calls by 40% and crash rates by 40%.