About the Role
At Arc , we are on a mission to amplify employees at local businesses using AI. With years of experience building and scaling commerce tools for businesses—from farmers markets and neighborhood coffee shops to global retailers, restaurant chains, and major sports venues—we know how to deliver mission-critical technology that integrates easily, delights customers, and works every time.
Voice drive-thru is our first product on that journey: an AI voice agent that takes real orders at the drive-thru speaker, in real time, integrating directly with a business's existing POS and hardware. Every order runs through a physical device we build and maintain ourselves — a microcontroller wired into the lane's audio and vehicle-detection hardware, paired with an edge compute node that streams audio to and from our backend. Done well, this means more revenue, faster lines, and fewer mistakes for the operators we serve — and it means the hardware and firmware underneath it have to work every single time, with no one around to reboot it.
As an Embedded Software Engineer, you'll own the software that runs on our edge devices in the field: the microcontroller firmware controlling status LEDs, audio bypass relays, and vehicle detection, and the host application that keeps audio flowing reliably between our hardware and the cloud. This is a high-leverage, high-autonomy role for someone who wants to shape how a physical product behaves in the real world, not just execute tickets.
What You'll Do
• Design and evolve firmware for our microcontrollers, handling status indication, physical audio bypass relays, and vehicle detection signal routing with hard reliability guarantees
• Build and harden the host application that runs on our edge compute nodes, managing the full-duplex, multi-process audio pipeline (capture, encode, playback) that connects drive-thru hardware to our cloud backend in real time
• Own the serial protocol and health-monitoring layer between microcontroller and host, including failure detection, exponential-backoff recovery, and state persistence across restarts — the device has to recover gracefully with nobody watching it
• Work across the hardware/software boundary: debug issues that span audio drivers, USB serial, relays, and third-party POS integrations, often with only logs and telemetry from a device installed at a restaurant hundreds of miles away
• Improve how we deploy, monitor, and remotely manage fleets of physical devices in production — LaunchAgent/systemd deployment, telemetry, remote access, and safe over-the-air updates
• Partner closely with product and operations to translate the real-world, on-the-ground constraints of drive-thru lanes and legacy hardware into robust technical solutions
What We're Looking For
• 5+ years of professional software engineering experience, including meaningful time in embedded systems, firmware, or hardware-adjacent software
• Comfort in C++ for resource-constrained microcontrollers, plus strong general-purpose backend skills in Python or any other modern languages
• Experience designing for reliability in real-time or latency-sensitive systems, especially ones that run unattended in the field
• Practical experience with serial/USB protocols, audio I/O, or similar low-level hardware interfaces
• Comfort operating with ambiguity — you can take a loosely defined hardware/software problem and drive it to a well-architected solution
• Strong judgment about when to build for scale vs. when to move fast — and the communication skills to bring others along with your reasoning
• Bonus: experience with audio processing/DSP, echo cancellation, remote fleet management, or point-of-sale/legacy hardware integrations
Why Join Us
You'll have significant influence over both the product and the engineering culture at an early-stage company solving a genuinely hard, high-stakes problem: physical devices that have to work flawlessly at real drive-thru lanes, in service of a mission to help local businesses run better. Voice drive-thru is just the beginning — your decisions will help shape what comes next.