Principal Engineer - Android

Our Story:

At COSMO, we inspire kids through innovative technology and a supportive community. Our family-centric products, such as the award-winning JrTrack Kids Smartwatch, enhance children's independence and confidence. This all-in-one device functions as a phone, GPS tracker, and music player, managed via the Mission Control Parent App, which allows parents to set safety alerts and manage contacts. Recognized as a top kids' wearable by PCMag and others, Cosmo is on the rise.

About the Role

Department: Engineering

Role Summary: We are looking for a Principal Engineer to set the technical direction for our Android platform and raise the engineering bar across the organization. As the most senior individual contributor on the team, you will own the hardest architectural problems, define the standards other engineers build to, and drive multi-quarter technical strategy that spans teams and products. This is a deeply hands-on role with org-wide influence: you will still write and review code and lead execution, but your largest impact comes from your technical judgment, your depth in one or more critical domains, and your ability to grow the engineers and processes around you.

Core Responsibilities

• Set technical strategy and own the architecture, reliability, performance, and security of the Android platform across teams and products.
• Serve as the deep technical authority in one or more critical domains (for example GNSS, calling, networking, connectivity, power, or system services) and act as the go-to problem solver when those systems fail in hard-to-diagnose ways.
• Lead technical design end to end: scope ambiguous problems, evaluate tradeoffs, produce and review design docs, and align teams and stakeholders on the approach.
• Own the AIDL interfaces and communication between Android components, and the integration of hardware drivers and services with system and product applications.
• Lead resolution of the hardest cross-layer issues spanning hardware, system services, performance, battery, memory, networking, and applications.
• Define and model the engineering process the team builds to: PRs linked to tickets, unit test coverage, dev testing, rigorous code review, and hold the bar through your own reviews.
• Lead and participate in agile ceremonies (daily standup, story refinement, retrospectives) and help the team break large initiatives into well-scoped, parallel workstreams.
• Operate across multiple concurrent workstreams, sequencing and unblocking them without losing technical depth on any.
• Mentor engineers at every level, including onboarding and ramping new hires, and grow the next generation of senior and lead engineers.
• Act as the senior technical point of contact for hardware, firmware, product, design, and QA teams, and translate between them.
• Drive platform-wide standards, tooling, and best practices, and influence the technical roadmap beyond any single area.
• Set direction on AI-assisted development, driving adoption across the team where it provides measurable improvements in quality or productivity.

What You'll Bring

Required Experience

• 8+ years of professional software engineering experience, with 6+ years focused on Android.
• 4+ years acting as a technical leader or principal-level IC, setting direction and mentoring engineers across teams.
• Deep, demonstrable expertise in one or more platform domains such as GPS, calling, networking, connectivity, or system services (3+ years of focused depth).
• 7+ years hands-on with Android SDK, Android Studio, Kotlin, and Java.
• 4+ years hands-on with AOSP, Android framework, system services, privileged apps, HALs, or custom Android devices.
• Deep knowledge of Binder, AIDL, drivers, and hardware-to-application data flow (4+ years).
• Expert understanding of Android architecture, security, performance, and UI development.
• 4+ years with MVVM or Clean Architecture, modularization, Dagger or Hilt, Coroutines, Flow, or RxJava.
• Experience with XML Views and Jetpack Compose (3+ years).
• Expert testing and debugging skills using tools such as JUnit, Robolectric, Espresso, logs, traces, and bug reports.
• 4+ years working with CI/CD, feature flags, analytics, staged releases, and large codebases.
• A track record of setting and upholding engineering processes (PR hygiene, unit testing, dev testing, code review) across a team.
• A proven history of sound architecture and tradeoff decisions under ambiguity and constraint, at a scope that affected multiple teams or products.
• Excellent communication, ownership, and problem-solving skills, with a demonstrated ability to drive alignment across the org.

Nice to Have

• Deep experience with smartwatches, wearables, IoT, embedded Android, or other custom hardware (3+ years).
• Experience with Linux drivers, JNI, C/C++, Soong, or the AOSP build system.
• Published Android applications or open-source contributions.
• Experience with design systems and global product releases.
• Experience defining engineering process, tooling, or release infrastructure at the org level.
• Familiarity with responsible AI-assisted development practices.

Skills & Attributes

• Fluent in English
• Strong technical ownership and decision-making mindset
• Comfortable coordinating across time zones and cultures
• Organized, clear communicator who surfaces risks early
• Calm and effective in fast-moving, ambiguous environments

What We Offer

• Competitive salary and benefits including 100% employer paid supplemental medical policy 
• Remote working environment
• An opportunity to make a significant impact in a fast-growing company
• Generous PTO
• Collaborative, creative, and supportive work environment