Lead Firmware Engineer (ESP32 / USB Host / BLE / Cryptography)

About the role

We are looking for a Lead Firmware Engineer to drive the development of a secure USB‑to‑BLE Smart Card Bridge for our next‑generation financial technology platform. The role involves designing, implementing and maintaining production‑grade firmware on ESP32 hardware, ensuring high‑performance BLE communication and robust cryptographic handling.

Key responsibilities

• Lead architecture and design of embedded C/C++ firmware for a custom USB‑to‑BLE bridge.
• Implement and optimise the USB Host stack, supporting CCID protocol and power delivery.
• Develop a secure BLE 5.0 GATT server with custom services for low‑latency APDU transmission.
• Parse, format and sequence ISO‑7816 APDU commands between host application and smart‑card chip.
• Collaborate on hardware schematic reviews, manage power states, 5 V boost converters, LiPo battery monitoring and deep‑sleep/wake‑up mechanisms.
• Enforce firmware security hardening, including handling of session tokens, buffer‑overflow protection and memory zeroing of sensitive data.
• Work with FreeRTOS to schedule real‑time tasks and ensure deterministic performance.

Required profile

• 7+ years of professional experience in embedded firmware development.
• Proven track record of delivering production‑grade firmware for security‑sensitive applications.
• Strong understanding of hardware‑software integration and power‑management techniques.

Required skills

• Embedded C/C++ and ESP‑IDF.
• USB Host stack development (USB 2.0, CCID class).
• BLE 5.0 stack configuration and GATT server design.
• ISO‑7816 smart‑card standards and APDU command handling.
• Cryptographic primitives (SHA‑256, RSA, ECC) and secure key management.
• FreeRTOS real‑time operating system.
• Power‑management hardware (5 V boost converters, LiPo battery monitoring, deep‑sleep).
• Hardware schematic review and firmware‑hardware co‑design.