Firmware Engineer

ButterflyMX is on a mission to empower people to automate property access operations and security from a single platform. Our products are installed in more than 20000 multifamily commercial gated communities and student-housing properties worldwide including properties developed owned and managed by the most trusted names in real estate. Our features are designed for developers owners property managers and tenants and our products lower operating costs and improve tenant satisfaction.

Developers and owners no longer need to run building wiring or install in-unit hardware. Property managers can grant building access revoke permissions and review entry logs from an online dashboard. Residents can open doors from their smartphones issue visitor access and see who is trying to enter the building.

Fantastic people are the key to our success. As a distributed primarily remote workforce were looking for more intelligent passionate collaborative ai-forward and down-to-earth individuals to join our growing team. Were driven by a shared commitment to excellence and innovation grounded in our core values: We delight our customers We take ownership We are a community of collaborators We speak up We think big and do small and We are tenacious.

At ButterflyMX firmware sits at the critical intersection of electronics embedded systems product reliability device security and customer experience. We are seeking an exceptional Firmware Engineer to help design build debug secure and optimize the embedded software that powers our next generation of access control intercom IoT wireless and connected hardware products.

This role requires a rare combination of strong firmware development skill deep hardware intuition and practical embedded systems judgment. The successful candidate will be comfortable working close to the hardware registers buses timing interrupts memory power analog behavior digital interfaces and real-world failure modes while also understanding how embedded devices interact with secure cloud-connected systems.

Our products span multiple embedded environments including bare-metal microcontroller firmware with main-loop architectures RTOS-based systems including Zephyr and embedded Linux platforms. This engineer must be able to write production-quality code independently analyze and optimize firmware at a low level troubleshoot hardware/firmware interactions and use AI tools intelligently to accelerate development without outsourcing engineering judgment.

This is a hands-on high-impact engineering role for someone with initiative tenacity curiosity and the ability to solve ambiguous problems across hardware firmware manufacturing and field reliability.

• Develop Production-Ready Embedded Firmware

• Design write debug and maintain firmware across bare-metal RTOS/Zephyr and embedded Linux platforms.

• Build reliable low-level firmware in C/C and other relevant firmware languages for microcontrollers peripherals sensors communication interfaces power systems and device control logic.

• Develop main-loop interrupt-driven event-driven and multithreaded architectures optimized for timing memory latency power boot time and long-term reliability.

• Own firmware from board bring-up and prototype development through EVT/DVT/PVT production release and post-launch support.

• Bridge Hardware Firmware and Real-World System Behavior

• Work close to the hardware including registers buses interrupts ADCs power rails signal integrity timing noise grounding and analog/digital interactions.

• Read schematics understand PCB layouts and collaborate with electrical and mechanical engineers on architecture bring-up manufacturability thermal behavior EMI/EMC and field installation constraints.

• Diagnose multi-domain failures using oscilloscopes logic analyzers debuggers multimeters power analyzers and other lab tools.

• Build firmware that is resilient to power instability brownouts signal noise temperature extremes communication faults installation variability and device aging.

• Build Secure Connected IoT Device Firmware

• Implement secure boot bootloaders chain of trust signed firmware certificate signing key provisioning device identity and image validation.

• Support secure OTA updates rollback protection version control recovery behavior and firmware authenticity.

• Develop secure device-to-cloud and device-to-controller communication using appropriate authentication cryptographic and transport-layer protections.

• Partner with security cloud and systems teams on device hardening credential management threat modeling and secure manufacturing provisioning.

• Implement Embedded Communication Protocols

• Develop and debug firmware for I2C SPI UART GPIO ADC PWM RS-485 USB Ethernet BLE Wi-Fi and cellular-connected systems as applicable.

• Implement reliable protocol handlers for access control device-to-device device-to-controller and device-to-cloud communication.

• Build robust error handling retries timeouts diagnostics telemetry and graceful degradation into communication paths.

• Create and maintain Interface Control Documents protocol specifications state diagrams register maps and integration documentation.

• Drive Firmware Quality Testability and Reliability

• Design firmware with observability diagnostics manufacturability and field support in mind from the beginning.

• Support built-in self-test production test firmware manufacturing diagnostics burn-in hardware validation and release readiness workflows.

• Develop unit tests integration tests hardware-in-the-loop tests regression tests and automated validation tools where appropriate.

• Use disciplined engineering practices including code review version control CI/CD static analysis issue tracking release notes and root-cause documentation.

• Partner with Quality Support Manufacturing and Operations to analyze RMA trends field failures intermittent faults and reliability issues.

• Use AI Tools Responsibly to Increase Engineering Leverage

• Use AI models and engineering tools to accelerate code development debugging test creation documentation and design exploration.

• Independently validate AI-generated code assumptions and recommendations before using them in production systems.

• Maintain full ability to write review debug optimize and explain firmware without relying on AI as a substitute for engineering judgment.

• Solve Ambiguous Problems with Initiative and Tenacity

• Approach problems holistically across electronics firmware mechanical constraints manufacturing variation installation conditions cloud interaction and customer impact.

• Prototype quickly test carefully learn from data and iterate toward robust production-ready designs.

• Challenge assumptions identify hidden failure modes communicate tradeoffs clearly and propose better architectures when the obvious path is not good enough.

• 5 years of hands-on embedded firmware development experience; 8 years is preferred for senior-level candidates.

• Strong firmware development skills in C/C with experience writing production code for resource-constrained embedded systems.

• Hands-on experience with bare-metal microcontroller firmware RTOS-based systems and embedded Linux. Experience with Zephyr is strongly preferred.

• Strong understanding of microcontroller architecture interrupts timers DMA memory maps bootloaders watchdogs peripheral drivers low-power modes and low-level register programming.

• Deep practical understanding of electronics hardware including digital and analog domains power regulation ADCs signal conditioning filtering impedance noise grounding and signal integrity.

• Experience debugging real hardware using oscilloscopes logic analyzers debuggers programmers multimeters and other lab equipment.

• Experience with embedded communication interfaces such as I2C SPI UART CAN RS-485 USB BLE Wi-Fi Ethernet and cellular-connected systems.

• Experience with secure boot firmware signing certificate signing device identity key provisioning encrypted communications and secure OTA update mechanisms.

• Experience developing firmware for connected IoT products ideally including products deployed in commercial industrial access control building systems consumer electronics or field-installed environments.

• Familiarity with higher-level communication patterns and protocols such as MQTT REST WebSockets TLS device-to-cloud APIs and remote device management.

• Ability to read schematics understand PCB layouts reason about hardware behavior and collaborate effectively with electrical engineers.

• Ability to troubleshoot multi-domain failures involving hardware firmware networking environment manufacturing and customer installation factors.

• Experience with Git CI/CD automated testing static analysis issue tracking release management and disciplined software development practices.

• Strong documentation skills including design notes ICDs state diagrams test plans debug guides release notes and technical decision records.

• Strong initiative tenacity lateral thinking and comfort operating in fast-moving product development environments.

• AI-forward mindset with the engineering maturity to use AI tools as accelerants not substitutes for deep technical understanding.

The expected base salary range for this position is $150000-$190000 Actual compensation will depend on factors including budget skills experience location and internal equity. This position may also be eligible for bonuses equity or other forms of compensation where applicable.

• Comprehensive Medical Dental and Vision plans (ButterflyMX covers 80% of the cost) starting day 1

• 401(k) plan with a match

• 10 paid holidays 20 vacation days 5 sick days 3 floating holidays

• Basic Life and Accidental Death and Dismemberment Insurance (ButterflyMX covers 100% of the cost)

• Short and Long Term Disability (ButterflyMX covers 100% of the cost)

• Paid Family Leave

• Employee Assistance Program

• Quarterly self-care stipends

• Access to optional benefits including pre-tax flexible healthcare spending accounts (FSA and HSA) Dependent Care FSA and Commuter Benefits as well as optional Supplemental Life AD&D Hospital Indemnity Legal Accident Critical Illness Pet and Personal Liability Insurance

• And more!

ButterflyMX is an equal opportunity employer and we value diversity at our company. We do not discriminate on the basis of race religion color national origin gender sexual orientation age marital status veteran status or disability status. You must have the authorization to work in the US to become an employee. We strive to create an accessible and inclusive experience for all candidates and employees. If you need reasonable accommodations during the application or the recruiting process please let our recruiting team know.

Required Experience:

IC