Firmware Engineer

Magical Toys is a San Francisco–based startup crafting voice-first, connected play experiences. Our current platform centers on an ESP32-S3–powered interactive toy with low-power wake-word, full-duplex audio, BLE/Wi-Fi onboarding, OTA updates, and delightful LED interactions—built to be safe, resilient, and fun. About the Role You’ll be the go-to firmware engineer advancing our ESP32 stack for real-time audio, connectivity, and low-power operation. You’ll ship features that make our characters feel alive: reliable wake-word, smooth streaming, robust provisioning, and battery-friendly behaviors. You’ll work closely with hardware, audio/DSP, and mobile to iterate rapidly on product. What You’ll Do Develop and optimize ESP32 firmware (ESP-IDF + FreeRTOS) for connectivity, audio, and power management. Implement and harden Wi‑Fi (802.11) features including provisioning, secure transport, and reconnection logic. Integrate WebSockets (and related real-time channels) for low-latency device-cloud messaging. Contribute to real-time audio features: I²S pipeline, VAD/wake‑word (e.g., WakeNet), buffering, and playback. Enhance low-power behavior (light/deep sleep, wake sources) while meeting latency and UX targets. Build and maintain BLE flows (e.g., first-time onboarding, device info, diagnostics). Own OTA reliability (rollback, versioning, staged rollout) and on-device logging/metrics. Debug with logic analyzers/J-Link/serial trace; write crisp documentation and code reviews; collaborate cross-functionally. Required Qualifications 3–5 years professional embedded experience (ESP32, STM32, nRF, or similar). Strong C/C++ in RTOS environments; comfort with ESP‑IDF, FreeRTOS, CMake, and IDF Monitor. Hands-on Wi‑Fi development (802.11), plus experience with real-time messaging (WebSockets/MQTT). Familiar with voice/wake‑word frameworks (e.g., WakeNet or equivalent) and I²S audio basics. Solid grasp of SPI/I²C/UART and low-level bring-up. Excellent problem-solving; thrives in a fast-paced, lab-centric, small-team setting. Preferred Qualifications IoT security: TLS, certificate provisioning, secure boot, and flash encryption. Audio/DSP exposure: AEC/NS/AGC, streaming buffers, and clocking on constrained MCUs. Real-time comms on embedded or at the edge (e.g., RTP/WebRTC on gateway, or similar architectures). OTA pipelines at scale; factory firmware, self-test, or DFM/DFT collaboration. Contributions to open source or demonstrable personal prototypes. Why Join Magical Toys? Ship tangible, joyful products that blend hardware, firmware, and a touch of wonder. Tight feedback loops: on-bench testing, rapid iterations, and direct impact on user experience. Supportive, collaborative team that values craft, balance, and growth. Medical Insurance Provided to full-time staff To apply Send your resume and a brief note on your most relevant ESP32 work (links to repos/demos welcome) to [email placeholder]. Magical Toys is an equal opportunity employer—diversity and inclusion are core to how we build.

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