Staff Software Engineer, Mobile Security

OKX will be prioritising applicants who have a current right to work in Hong Kong, and do not require OKX's sponsorship of a visa. Please note that Hong Kong is a group-level service hub, and OKX does not carry on a business of operating a virtual asset trading platform in Hong Kong. Who We Are At OKX, we believe that the future will be reshaped by crypto, and ultimately contribute to every individual's freedom. OKX is a leading crypto exchange, and the developer of OKX Wallet, giving millions access to crypto trading and decentralized crypto applications (dApps). OKX is also a trusted brand by hundreds of large institutions seeking access to crypto markets. We are safe and reliable, backed by our Proof of Reserves. Across our multiple offices globally, we are united by our core principles: We Before Me, Do the Right Thing, and Get Things Done. These shared values drive our culture, shape our processes, and foster a friendly, rewarding, and diverse environment for every OK-er. OKX is part of OKG, a group that brings the value of Blockchain to users around the world, through our leading products OKX, OKX Wallet, OKLink and more. About The Opportunity We are looking for a Staff Mobile Security Engineer to join our Mobile Security team, where you will play a key role in identifying and mitigating security vulnerabilities across OKX's mobile applications and platforms. This is a high-ownership role at the intersection of offensive security, mobile engineering, and platform protection — you will work closely with development, operations, and compliance teams to ensure security is embedded at every layer of our mobile stack. You bring deep expertise in mobile application security, offensive techniques, and secure coding practices. You are also fluent in AI-assisted development and bring the discipline to build, maintain, and continuously improve your own AI engineering workflows. What You'll Be Doing • Identify and address security vulnerabilities in mobile code, systems, and networks through manual review, automated tooling, and threat modelling. • Manage and optimise application security tools, processes, and alerts to maintain a strong security posture. • Validate and respond to Bug Bounty submissions, triaging findings and coordinating remediation with engineering teams. • Produce detailed security findings reports and present them to both technical and management audiences, contributing to real-world attack prevention. • Collaborate with development teams to implement and champion secure coding practices across iOS and Android platforms. • Apply AI tools to accelerate security research, automate vulnerability detection workflows, and improve the efficiency of threat analysis. • Work alongside operations and compliance teams to ensure security is a consistent priority across the organisation. • Participate in incident response and management activities. • Stay current on the latest offensive security techniques, application security threats, and industry best practices. What We Look For In You • 5+ years of experience in mobile application security or offensive security, with hands-on expertise in iOS and/or Android platforms. • In-depth understanding of security risks, vulnerabilities, and concepts in mobile and web applications. • Proficient in code review across Kotlin, Swift, TypeScript, or JavaScript, with a strong grasp of application security threats. • Able to create proof-of-concepts (PoCs) to demonstrate vulnerabilities, review patch code for adherence to standards, and collaborate with repository owners on remediation. • Actively uses AI tools in your security engineering workflow — including building AI-leveraged workflows and codifying repeatable agent skills so tools like Claude Code or Codex deliver reliably on real production work. • Strong analytical and problem-solving abilities with excellent verbal and written communication skills. Nice-To-Haves • Prior experience developing mobile security SDKs at scale — products with a daily active user base of over ten million. • Experience in large-scale business risk control projects, or practical experience in threat intelligence, business risk prevention, and countermeasures against black and grey industries. • In-depth reverse engineering of major apps from first-tier vendors, or other projects that demonstrate strong reverse engineering capabilities. • Proficiency in ARM assembly, with the ability to implement deep-level countermeasures at the native and application layers. • Experience with device fingerprint recognition — including simulating new devices through methods such as flashing, modification, and application cloning. • Ability to work across multiple mobile platforms simultaneously. Perks & Benefits • Competitive total compensation package • L&D programs and Education subsidy for employees' growth and development • Various team building programs and company events • Wellness and meal allowances • Comprehensive healthcare schemes for employees and dependants • More that we love to tell you along the process! #LI-ML1 #LI-ONSITE Please note that Hong Kong is a group-level service hub, and OKX does not carry on a business of operating a virtual asset trading platform in Hong Kong. Notice: All official OKX vacancies are published on this website. While roles may appear on selected third-party platforms from time to time, information on other sites may be inaccurate or outdated. If in doubt, please apply directly through our official careers website. Information collected and processed as part of the recruitment process of any job application you choose to submit is subject to OKX's Candidate Privacy Notice.