Lead Mobile Engineer

New York City
About Citizen

Citizen’s mission is to protect the world. We began by opening the NYC and San Francisco 911 system to local Citizen app users, creating access to real-time crime and safety information. By increasing situational awareness and transparency, we hope communities will become safer than ever before.

Since our launch, 3% of New Yorkers use our app every month, and that growth is accelerating. We launched San Francisco last fall, and over 1% has already joined the Citizen safety network. We send over 4 million nearby crime notifications each month, alerting our users to emergencies and dangerous situations near them. Citizen broke both recent NYC terror incidents to people nearby, keeping thousands in the vicinity safer and informed in real-time. Citizen has been featured on local NYC news over 100 times in the past 3 months. 

We’re looking for passionate, mission-driven individuals to help take the Citizen app to the next level as we scale up new cities and expand globally.

Citizen is backed by Sequoia Capital and Founder’s Fund. 

Our Challenges

    • Scaling: We have one of the fastest growing organic user bases in NYC, and right now we’re geo-restricted to New York City and San Francisco. Soon we will launch nationwide and we need to support that scale. A Citizen international launch will follow.
    • Bursting: Without warning, a major incident occurs and multiple users begin live-streaming video into the app. We notify the entire user base, causing a massive burst of simultaneously connected clients. The core systems we build need to efficiently support traffic that can grow to hundreds of thousands of concurrent users today, and millions in the future.
    • Analytics: We want to alert users to incidents that matter to them, in a way that scales across different geographic densities and demographics.
    • Mobile video streaming: Our app will ingest high-quality video at low-latency, transcode, and redistribute the video to external media outlets seamlessly.
    • Extracting signal from noise: During major breaking news events, tensions are high and a lack of information persists. We build tools to raise facts and suppress noise.
    • FM radio: We use software-defined radios to consume all radio dispatch in NYC, SF and eventually every major city, whether analog, digital, or trunked.

Our Stack - languages and technologies we use and teach

    • Mobile: Swift (iOS), Java (Android)
    • Web: React.js
    • Server: Go, Node (for isolated systems)
    • Systems: MySQL, Redis, Kafka, Firebase (for isolated systems)
    • Infrastructure: Kubernetes on GCP

Role Description

    • We reach our users through our mobile app. We’re in the hands of hundreds of thousands of people in New York City already, and need to scale to millions. As we grow into new cities, we’ll have to support multiple languages and devices. We’ll want to be present on iPad, Android tablets, displays, etc. 
    • The Lead Mobile Engineer will lead the overall technical direction of both iOS and Android, work closely with Product to manage the roadmap, and with Engineering on overall data flow from backend to mobile to frontend systems. 
    • Effectively manage our release cycles, balancing feature development with infrastructure investment. 
    • Represent the Mobile team in planning and executive meetings, communicating the priorities, progress, and impact of team goals. 
    • Implement engineering processes and policies that emphasize quality and progress to shape the future of mobile at Citizen. 


    • Bachelor’s Degree in Computer Science or related field
    • 7+ years experience as a developer building applications either for iOS or Android (both is ideal).
    • Experience building, shipping, and scaling consumer facing applications.
    • Experience building components that enable fellow developers is a huge plus.
    • Track record of building and leading productive, high functioning engineering teams.
    • Aptitude with numbers, intellectual curiosity about metrics and measuring impact.
    • Enjoys coaching and collaborating with others.