Senior Software Engineer, Client Security

Responsibilities

Client Security is part of the Business Risk Integrated Control (BRIC) team. We focus on building end-to-end, defense-in-depth systems that balance privacy and business needs to combat large-scale automated fraud and API abuse. Our scope includes client environment inspection, risky signal collection, trusted computing, traffic validation, data mining, and delivering tools and subject-matter services to business lines. Responsibilities: - Client-side security engineering: Develop, iterate, maintain, and provide technical support for client-side security components across Android, iOS, macOS, and Windows. - Binary and runtime protection: Research and implement cutting-edge techniques to detect and prevent app cracking, tampering, hooking/injection, automation attacks, and other large-scale abuse; drive competitive analysis and key technical breakthroughs to strengthen defenses and product experience. - Cross-functional threat response: Collaborate with client, backend, risk, and privacy stakeholders to research malicious tooling, track emerging attacks, and build anti-automation and validation systems. - AI-driven automation defense: Build client-side defenses against AI-driven automation (LLM-assisted/scripted bots), including behavior modeling, anomaly detection, and proof-of-human signal design. - On-device ML and content integrity: Secure on-device ML components used in product features-covering model integrity verification, anti-tamper/anti-extraction, encrypted model loading, and secure inference runtimes (e.g., TEE/Secure Enclave)-and research adversarial ML and deepfake vectors impacting client features (e.g., biometrics, media, content) to design on-device detection and mitigation pipelines.

Qualifications

Minimum Qualifications - Strong passion for information security with hands-on experience in binary security and reverse engineering, including code obfuscation, VMP/virtualization, anti-debugging, anti-injection, and malware analysis. - Deep understanding of OS internals; proficiency in C/C++, Objective-C, and Java; familiarity with ARM/x86 assembly; solid programming skills and clean coding habits. - Cross-platform client security experience is preferred; expert-level proficiency in at least one platform (Android, iOS, macOS, or Windows) with the ability to deliver independently. - Working knowledge of AI security and adversarial ML concepts (e.g., evasion/poisoning attacks, model extraction/inversion, jailbreak/prompt-injection, data exfiltration) and their impact on client-side defenses. - Experience designing signals and features to differentiate human-device interactions from automated agents and reducing false positives under privacy constraints. Preferred Qualifications - Experience with TEE/TrustZone/Secure Enclave, device/app attestation, and secure traffic validation. - Familiarity with Frida, Xposed, Clang/LLVM, static/dynamic analysis, and symbol/identifier obfuscation and hardening pipelines; experience building large-scale anti-automation and validation systems. - Experience with on-device ML frameworks (e.g., TensorFlow Lite, PyTorch Mobile, Core ML, Metal, NNAPI) and secure model deployment (e.g., encryption, integrity checks, guarded runtime), as well as client-side bot detection leveraging ML, deepfake/synthetic media detection, content provenance/watermark verification (e.g., C2PA), and privacy-preserving ML (e.g., differential privacy/federated approaches). - Prior AI red teaming or attack tooling development (e.g., prompt-injection harnesses, adversarial example generation) and collaboration with applied ML teams on guardrails and monitoring.

Job Information

[For Pay Transparency]Compensation Description (Annually)

The base salary range for this position in the selected city is $212800 - $387600 annually.

Compensation may vary outside of this range depending on a number of factors, including a candidate's qualifications, skills, competencies and experience, and location. Base pay is one part of the Total Package that is provided to compensate and recognize employees for their work, and this role may be eligible for additional discretionary bonuses/incentives, and restricted stock units.

Benefits may vary depending on the nature of employment and the country work location. Employees have day one access to medical, dental, and vision insurance, a 401(k) savings plan with company match, paid parental leave, short-term and long-term disability coverage, life insurance, wellbeing benefits, among others. Employees also receive 10 paid holidays per year, 10 paid sick days per year and 17 days of Paid Personal Time (prorated upon hire with increasing accruals by tenure).

The Company reserves the right to modify or change these benefits programs at any time, with or without notice.

For Los Angeles County (unincorporated) Candidates:

Qualified applicants with arrest or conviction records will be considered for employment in accordance with all federal, state, and local laws including the Los Angeles County Fair Chance Ordinance for Employers and the California Fair Chance Act. Our company believes that criminal history may have a direct, adverse and negative relationship on the following job duties, potentially resulting in the withdrawal of the conditional offer of employment:

1. Interacting and occasionally having unsupervised contact with internal/external clients and/or colleagues;

2. Appropriately handling and managing confidential information including proprietary and trade secret information and access to information technology systems; and

3. Exercising sound judgment.

About TikTok

TikTok is the leading destination for short-form mobile video. At TikTok, our mission is to inspire creativity and bring joy. TikTok's global headquarters are in Los Angeles and Singapore, and we also have offices in New York City, London, Dublin, Paris, Berlin, Dubai, Jakarta, Seoul, and Tokyo.

Why Join Us

Inspiring creativity is at the core of TikTok's mission. Our innovative product is built to help people authentically express themselves, discover and connect - and our global, diverse teams make that possible. Together, we create value for our communities, inspire creativity and bring joy - a mission we work towards every day.

We strive to do great things with great people. We lead with curiosity, humility, and a desire to make impact in a rapidly growing tech company. Every challenge is an opportunity to learn and innovate as one team. We're resilient and embrace challenges as they come. By constantly iterating and fostering an "Always Day 1" mindset, we achieve meaningful breakthroughs for ourselves, our company, and our users. When we create and grow together, the possibilities are limitless. Join us.

Diversity & Inclusion

TikTok is committed to creating an inclusive space where employees are valued for their skills, experiences, and unique perspectives. Our platform connects people from across the globe and so does our workplace. At TikTok, our mission is to inspire creativity and bring joy. To achieve that goal, we are committed to celebrating our diverse voices and to creating an environment that reflects the many communities we reach. We are passionate about this and hope you are too.

TikTok Accommodation

TikTok is committed to providing reasonable accommodations in our recruitment processes for candidates with disabilities, pregnancy, sincerely held religious beliefs or other reasons protected by applicable laws. If you need assistance or a reasonable accommodation, please reach out to us at