Senior Firmware Engineer

About the Role Join a Y Combinator-backed wearable technology startup as a Senior Firmware Engineer on the core hardware team. You'll help define the firmware architecture and take a next-generation, AI-powered wearable device from prototype all the way to mass production. This is a high-impact, hands-on role at the intersection of low-power embedded design, sensor integration, and production engineering — with the opportunity to ship a category-defining consumer product from the ground up. The team is small, tight-knit, and works in person in New York City. You'll collaborate daily with hardware, algorithms, product, and industrial design colleagues, and your work will directly shape the device that reaches end users. 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 interrupt-driven designs. Optimize firmware performance, memory usage, latency, and overall reliability. Lead board bring-up, debugging, validation, and manufacturing support. 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 wearable or consumer electronics from development through 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). Solid experience with ARM Cortex-M microcontrollers and modern debugging tools. Hands-on experience with power management architectures for low-power embedded systems. Experience building multi-core embedded data pipelines for real-time sensor acquisition. Sensor integration experience using SPI, I2C, UART, GPIO, DMA, and interrupt-driven designs. Experience with board bring-up, debugging, validation, and manufacturing support. Comfortable working in person with a small, fast-moving startup team. Nice to Have Background in sensor fusion, signal processing, or biometric sensing. Experience with platforms such as Nordic, Qualcomm, Ambiq, or STMicroelectronics. Familiarity with secure bootloaders, OTA firmware updates, and embedded security practices. Experience specifically with wearable or health-tech devices. Familiarity with wireless certification processes. Location This is a full-time, on-site position based in New York City, NY . Candidates must be willing and able to work in person with the engineering team. Visa sponsorship is not available. Compensation & Benefits Compensation details were not provided for this role. You'll be joining at an early, high-equity stage of a Y Combinator-backed company, with meaningful ownership opportunity commensurate with your seniority and impact.