Embedded C Developer

Location: Denver, CO (4 days onsite/week)

Role: Embedded C Developer OpenSync/OpenWrt WiFi Router with Cellular

Interview: R2 F2F

JD:

Required Skills

5+ years of embedded C development on Linux-based platforms

Strong proficiency in C programming - pointers, memory management, IPC, event-driven architectures

Experience with OpenWrt build system, package management, UCI configuration, and JFFS2/SquashFS overlay filesystems

Familiarity with OpenSync or similar cloud-managed CPE frameworks (OVSDB, protobuf, MQTT telemetry)

Experience with cellular modem integration - AT commands, QMI, network interface management (rmnet/wwan)

Strong understanding of Linux networking - routing tables, metrics, netfilter, bridge interfaces, IPv4 and IPv6 dual-stack, neighbor discovery, DHCPv4/DHCPv6, SLAAC, and prefix delegation

Understanding of TLS handshake with mutual authentication using X.509 certificates, certificate chain validation, and secure provisioning

Knowledge of security and tunneling protocols - GRE tunneling, IPsec, VPN overlays, and secure encapsulation for cloud-managed traffic

Experience with event loop frameworks (libev, libuv, or similar)

Proficiency with debugging tools - GDB, strace, tcpdump, kernel logs, serial console

Familiarity with Git, GitLab CI/CD, cross-compilation toolchains

Understanding of WiFi standards (802.11ax/be) and wireless driver configuration

Top Skills:

1. Embedded C Development on Linux/OpenWrt

o C programming, Linux internals, debugging, IPC, event-driven design

2. OpenSync/OpenWrt Platform Development

o OpenSync Managers, OVSDB, UCI, MQTT, OpenWrt build system

3. Linux Networking & LTE/5G Cellular Integration

o Routing, IPv4/IPv6, failover, QMI/MBIM, modem management, GRE/IPsec