Senior Software Engineer - Android Systems & Security

PayJoy • San Francisco, CA

6d

About The Position

This is not a conventional Android app development role (building applications for the Play Store). We are seeking a specialized systems engineer focused on the heart of the operating system: AOSP (Android Open Source Project) and the TEE (Trusted Execution Environment). In this role, you will bridge the gap between high-level Android features and low-level hardware integration, ensuring our proprietary security mechanisms—which protect our assets at the OS level—are robust, performant, and tamper-proof.

Requirements

• Extensive, hands-on experience with AOSP development, including modifying system services and utilizing the Android build system (Soong/Make).
• Expert-level proficiency in Java and C/C++ (JNI). (Ability to read/write Kotlin is expected, but core work remains at the system level).
• Proven experience working with or for an OEM or chipset vendor on firmware customization, device bring-up, or security hardening.
• Demonstrable knowledge of AOSP and TEE / ARM TrustZone.
• If your background is primarily focused on building consumer-facing commercial apps (e.g., banking, gaming, or general retail apps), this role will not be a match for your skillset.

Nice To Haves

• Experience with Secure Boot, verified boot (AVB), and common Android exploit vectors.
• Automation of firmware build pipelines and signing processes using Python or Bash.
• Comfort collaborating effectively with international teams across different time zones.

Responsibilities

• Develop and maintain custom modifications within the Android Framework (AOSP) and Hardware Abstraction Layers (HAL).
• Partner with global smartphone manufacturers and chipset vendors to integrate PayJoy’s proprietary technology into factory firmware.
• Work daily with our China-based engineering team to align on technical specifications and manufacturing requirements.
• Implement new locking features that interact with system-level services for example Telephony, Power Management, and Device Policy Manager, etc…
• Use deep chip-level knowledge to troubleshoot integration issues across different silicon providers (Qualcomm, MediaTek, etc.).
• Contribute to OTA (Over-the-Air) updates and global device testing.

Benefits

• Local benefits depending on the country of hire
• Company-funded health insurance for employee and immediate family
• Company-funded employee life and disability insurance
• Paid vacation days, unlimited sick leave
• $2,000 USD annual Co-working travel perk
• $2,000 USD annual Professional Development perk
• Phone finance, headphone benefit, home office equipment allowance and wellness perks
• Catered lunches

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed