Senior Firmware Engineer

About the Role Join the core hardware team of a Y Combinator–backed consumer wearable startup as a Senior Firmware Engineer, helping build the firmware powering a next-generation wearable platform. You'll play a foundational role in defining the firmware architecture and taking a category-defining device from prototype all the way through to mass production. This role sits at the intersection of low-power embedded design, sensor integration, and production engineering — and it matters because the reliability and battery life of the product depend on the work you'll own. You'll be working in-person in New York City alongside a small, fast-moving engineering team. What You'll Do Architect and develop embedded firmware for battery-powered wearable devices. Own core systems for low-power wireless connectivity, sensor processing, and data pipelines. Design and optimize Bluetooth Low Energy (BLE) connectivity for ultra-low-power operation. Build robust power management systems to maximize battery life. Develop multi-core embedded data pipelines for real-time sensor acquisition and processing. Integrate biometric and environmental sensors via SPI, I2C, UART, GPIO, DMA, and interrupts. Optimize firmware for performance, memory usage, latency, and reliability. Lead board bring-up, debugging, validation, and manufacturing support. Collaborate closely with hardware, algorithms, product, and industrial design teams across the full product lifecycle. Establish firmware best practices, testing frameworks, and CI workflows. What We're Looking For Required 6+ years of embedded firmware engineering experience, with a track record of shipping battery-powered consumer electronics or wearables to production. Deep expertise in Bluetooth Low Energy (BLE) systems and low-power embedded architectures. Strong proficiency in Embedded C/C++ and RTOS-based systems (e.g., FreeRTOS, Zephyr). Hands-on experience with ARM Cortex-M microcontrollers and modern debugging tools. Experience building multi-core embedded data pipelines for real-time sensor acquisition. Proven power management architecture skills for always-on, low-power embedded systems. Sensor integration experience using SPI, I2C, UART, GPIO, DMA, and interrupt-driven designs. Experience with board bring-up, debugging, validation, and manufacturing support. Nice to Have Background in sensor fusion, signal processing, or biometric sensing. Experience with embedded platforms such as Nordic, Qualcomm, Ambiq, or STMicroelectronics. Familiarity with secure bootloaders, OTA firmware updates, and embedded security practices. Experience building wearable or health-tech devices. Comfort moving quickly in a fast-paced, collaborative startup environment. Compensation & Benefits Salary: $120,000 – $200,000 per year, depending on experience. Equity participation typical of an early-stage startup. Visa sponsorship: Not available at this time. Location This is a full-time, on-site role based in New York City, NY. The team works in person together — remote or fully distributed arrangements are not available for this position.