Introduction

OpenWrt is a Linux operating system for embedded devices that replaces vendor firmware with a fully writable, package-managed environment.

OpenWrt is a Linux operating system targeting embedded devices. Instead of trying to create a single, static firmware, OpenWrt provides a fully writable filesystem with package management. This frees you from the application selection and configuration provided by the vendor and allows you to customize the device through the use of packages to suit any application.

For developers, OpenWrt is the framework to build an application without having to build a complete firmware around it; for users this means the ability for full customization, to use the device in ways never envisioned.

Why OpenWrt instead of vendor firmware?

Most routers and embedded devices ship with read-only firmware that can only be upgraded as a whole. OpenWrt takes a different approach:

	Vendor firmware	OpenWrt
Filesystem	Read-only (squashfs or similar)	Fully writable (overlay filesystem)
Package management	None — fixed at factory	opkg package manager with thousands of packages
Configuration	Web UI provided by vendor	UCI (Unified Configuration Interface) + optional LuCI web UI
Customization	Limited to vendor options	Full control — install, remove, or replace any component
Updates	Whole-firmware only	Individual package updates

Key subsystems

Build system

The OpenWrt build system is a set of Makefiles and scripts that automate downloading, patching, and cross-compiling the Linux kernel and all user-space packages for a target architecture. Running make menuconfig lets you select the target platform, kernel options, and packages before the build.

UCI — Unified Configuration Interface

UCI is OpenWrt’s centralized configuration system. All system configuration is stored in plain-text files under /etc/config/. The uci command-line tool and the UCI API allow scripts and programs to read and write configuration without parsing arbitrary config file formats.

ubus — Micro Bus Architecture

ubus provides a lightweight inter-process communication (IPC) bus for OpenWrt daemons and scripts. It allows services to expose methods and events that other processes can call or subscribe to, similar in concept to D-Bus but optimized for embedded use.

procd — Process Management Daemon

procd is OpenWrt’s init system and process supervisor. It replaces traditional SysV init scripts with a structured JSON-based service definition format, handles hotplug events, and manages service dependencies and restart policies.

opkg — Package Manager

opkg is the lightweight package manager used on OpenWrt devices. It handles installing, upgrading, and removing packages from configured package feeds. All packages in the related repositories are installed via opkg.

LuCI — Web Interface

LuCI is OpenWrt’s modular web administration interface. It is built on Lua and provides a browser-based GUI for configuring the system through UCI. LuCI is optional and can be installed or removed via opkg.

Related repositories

The main OpenWrt repository contains the build system and core packages. Additional packages are maintained in separate repositories and pulled in via the feeds system.

LuCI

Modern and modular web interface to control the device via a browser.

Packages

Community repository of ported packages available for installation via opkg.

Routing

Packages focused on mesh and dynamic routing protocols.

Video

Packages for display servers and clients (Xorg and Wayland).

Who is OpenWrt for?

Home users

OpenWrt replaces your router’s stock firmware with a system you can actually control. You can:

• Install ad-blocking software (e.g., AdGuard Home or dnsmasq with blocklists)
• Configure VPN clients or servers (WireGuard, OpenVPN)
• Set up quality-of-service (QoS) rules to prioritize traffic
• Monitor network usage with detailed statistics
• Use your router as a lightweight NAS or print server

Start with the Firmware Selector to find a pre-built image for your device.

Developers

OpenWrt provides a complete cross-compilation toolchain and build system. You can:

• Port existing Linux software to embedded targets without writing a full firmware
• Use the SDK to build individual packages without a full source checkout
• Write UCI-integrated init scripts with procd service definitions
• Expose device APIs over ubus for integration with other systems
• Contribute packages to the community feeds

See the Quickstart guide to build your first custom firmware image.

Network engineers

OpenWrt supports a wide range of routing and networking protocols, making it suitable for professional and research deployments:

• Dynamic routing: OSPF, BGP, Babel, OLSR, Batman-adv (from the routing feed)
• VLAN configuration via DSA (Distributed Switch Architecture) or swconfig
• 802.11r/k/v fast roaming for enterprise Wi-Fi deployments
• Firewall based on nftables with a structured UCI configuration
• Traffic shaping with CAKE and other queuing disciplines

See Supported Devices for hardware platform details.

Next steps

Quickstart

Clone the source, update feeds, configure, and build your first firmware image.

Supported devices

Find your hardware platform and learn about supported architectures.