Embedded C Developers – OpenSync/OpenWrt

Title: Embedded C Developers – OpenSync/OpenWrt Wi-Fi Router with Cellular
Location: Denver, CO (4 days onsite a week)
Duration: 6 months (possibility of extension)

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

2. OpenSync/OpenWrt Platform Development
OpenSync Managers, OVSDB, UCI, MQTT, OpenWrt build system

3. Linux Networking & LTE/5G Cellular Integration
Routing, IPv4/IPv6, failover, QMI/MBIM, modem management, GRE/IPsec