Software Engineer, iOS - Securing Engineering, USDS

About the team

The Security Engineering team is missioned to run and operate security infrastructures, platforms and technologies, as well as to support cross-functional teams to protect our users, products and infrastructures. This team is responsible for enhancing security tools and identifying vulnerabilities, with a specific focus on content assurance and the application of large language models (LLMs). You'll collaborate cross-functionally with partners inside and outside TikTok to fortify our products and users' security, helping to establish TikTok as the most trusted platform.

Responsibilities

We are seeking a Software Engineer to be a core member of our Apple Platforms team. In this role, you will lead the design and development of an AppGuard security framework, specifically focusing on the monitoring and management of all egress/ingress traffic. You will be a key contributor in a greenfield environment, applying high-performance engines and Domain-Specific Languages (DSL) to ensure application assurance.

• Architect Security Solutions: Take ownership of the technical direction for AppGuard, from initial design to implementation on iOS and macOS.
• Traffic & Policy Control: Develop capabilities to monitor and cut-off application traffic based on dynamic rule updates and sampling
• Performance Engineering: Implement high-performance engines to execute DSL-based logic for real-time security judging.
• Tooling Development: Design and develop associated platforms for the integration, testing, validation, and profiling of sandbox components.
• Collaborate Cross-Functionally: Work with stakeholders to ensure security solutions meet operational needs without compromising user experience.

Minimum Qualifications

• BS/MS degree in Computer Science, Engineering, or a related field.
• 3+ years of experience in mobile and desktop app development for Apple platforms.
• Expertise in Objective-C and Swift, with a deep understanding of Darwin-based frameworks and system-level tools.
• Performance Optimization: Proven experience with memory management, network optimization, and battery efficiency.

Preferred Qualifications

• Hands-on experience with Network Extensions or system-level traffic filtering.
• Demonstrated ability to contribute to architectural design and translate business security goals into technical vision.
• Familiarity with AI-enabled development tools (e.g., Cursor, Replit) to accelerate core logic implementation.