Principal Mobile Developer

Fidelity Investments•Westlake, TX

About The Position

Develops and enhances full-stack web applications and native mobile applications using Test Driven Development (TDD) and automated testing to ensure stability, resilience, and strong code coverage. Builds native iOS applications using Swift and SwiftUI, and native Android applications using Kotlin and Compose. Designs and implements scalable back-end services, RESTful APIs, and microservices architecture. Executes end-to-end releases with automated Continuous Integration/Continuous Delivery (CI/CD) pipelines using Jenkins and platform-specific tooling for web and mobile deployments. Works with architecture, security, and User Experience (UX) design teams to deliver compliant, accessible, and user-friendly solutions aligned with Web Content Accessibility Guidelines (WCAG), Apple Human Interface Guidelines, and Material Design. Supports efficient engineering practices, including trunk-based development, feature toggles, and branch by abstraction, using CI/CD and testing tools. Develops back-end systems using cross-platform knowledge, API design, and security best practices including OAuth and OpenID Connect, and AWS EC2, Lambda, DynamoDB, and S3. Applies engineering best practices and security standards to ensure quality, maintainability, and compliance. The role owns technical decisions across the stack, coordinates feature development from concept through production deployment, mentors junior team members, contributes to technical roadmaps, and advises senior management on technical strategy. It also researches advancements in self-custody crypto wallet encryption to inform design decisions, strengthen security controls, and align with emerging standards. Fidelity states it will not provide immigration sponsorship for this position. Its onsite working model is transitioning through a phased rollout, with expectations varying by region and role and likely to evolve.

Requirements

Bachelor’s degree in Computer Science, Engineering, Information Technology, Information Systems, or a closely related field (or foreign education equivalent), and five years of experience as a Principal Mobile Developer or in a closely related occupation developing native iOS and Android applications and integrating them with back-end APIs in an Agile and DevOps environment; or a relevant master’s degree and three years of such experience.
Demonstrated expertise designing scalable backend services and microservices using Node.js, NestJS, or GraphQL, and building RESTful or GraphQL APIs with OAuth and OpenID Connect authentication and authorization, while ensuring security, performance, and maintainability across distributed systems.
Demonstrated expertise in native iOS development and testing using XCUITest, XCTest, Swift, SwiftUI, Objective-C, UIKit, and Combine, with VIPER or MVVM architecture patterns and the Apple App Store application lifecycle and release process.
Demonstrated expertise in native Android development and testing using Espresso, JUnit, Kotlin, Compose, Java, XML layouts, and Coroutines, with Clean Architecture patterns and the Google Play Store application lifecycle and release process.
Ability to create performant and accessible Android user experiences aligned with Material Design and Google Play guidelines.
Demonstrated expertise in technical solutioning, implementation support, code reviews, peer mentorship, estimation, requirements refinement, and cross-functional collaboration in an Agile environment.
Experience with Agile practices including sprint planning and iterative development, coordinating with product managers and stakeholders across multiple business units, and aligning business requirements with technical execution.
Knowledge of Test Driven Development, automated testing, CI/CD, security best practices, and engineering practices including trunk-based development, feature toggles, and branch by abstraction.

Responsibilities

Design, develop, and maintain full-stack features across back-end and native iOS and Android platforms.
Coordinate end-to-end feature development from concept through production deployment, taking ownership of technical decisions across the stack.
Build and maintain scalable microservices and RESTful or GraphQL APIs supporting web and mobile applications.
Develop comprehensive documentation for multiple applications or subsystems.
Plan and coordinate project schedules and assignments for multiple technology initiatives.
Advise on risk assessment and risk management strategies for engineering projects.
Provide technology solutions to daily issues and deliver technical evaluation estimates for upcoming initiatives.
Mentor junior team members.
Contribute to technical roadmap planning and advise senior management on technical strategy.
Monitor application performance, troubleshoot issues, and implement optimizations across the technology stack.
Research and evaluate advancements in self-custody crypto wallet encryption to inform design decisions, enhance security controls, and align with emerging standards.
Collaborate with architecture, security, and UX teams to deliver compliant, accessible, user-friendly solutions.
Execute end-to-end releases using automated CI/CD pipelines and web and mobile platform tooling.