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Play Quake 4 on modern systems with an open-source engine and game-code replacement built around the original retail assets.
Get Started | Features | Player Docs | Build from Source | Technical Reference
openQ4 is an open-source replacement for the Quake 4 engine and game binaries, built to keep the original game playable on modern PCs while improving presentation, audio, controls, packaging, and day-to-day usability.
It is designed for players who want the original Quake 4 experience with a cleaner path to running it on today's hardware.
Note
openQ4 does not include Quake 4 assets. You still need a legitimate Quake 4 copy from Steam or GOG.
Important
I am getting the question a lot - particularly in the past week or two (Aug 2026) - so I feel I need to emphasise this point now: openQ4 is not compatible with legacy Quake 4 game code. This includes the recent Awakening leak by Justin Marshall. This position won't (and cannot) change. An Awakening mod for openQ4 isn't off the cards, however.
Important
Another point to make, as sadly luddites have become more common rather than less in 2026 and certainly more vocal than ever. Yes, this software is mostly vibe coded and with the extensive work that has gone into it it wouldn't be humanly possible to achieve without a small studio. That does not mean it isn't thoroughly checked and tested by multiple people, it also doesn't mean it is unsafe for use, nor does it mean we don't understand the codebase. It does have a few remaining issues to iron out - remaining macOS support being the main one - but as feedback will show it is otherwise stable. Whether you choose to follow unsubstantiated claims by luddites is entirely up to you, but I would first take a moment to examine their track records before presuming their expertise and credibility on the matter.
- Modern display support for widescreen, ultrawide, multi-monitor, borderless, and fullscreen setups.
- Optional visual upgrades such as bloom, HDR, anti-aliasing, baked light grids, soft particles, and enhanced shadow options.
- Reliable OpenAL audio with compatibility-first voice handling; experimental macOS packages bundle OpenAL Soft so large stock levels are not constrained by Apple's legacy buffer pool.
- Improved input and quality-of-life features including controller support, better console UX, and modern settings behavior.
- Single-player and multiplayer in one install with active compatibility work aimed at the stock game.
- Smarter repeat level loads with exact-match learned source preparation and validated local model, world, collision, and animation caches that fall back safely to the installed assets.
- A stock-map Arena Campaign (experimental) with five escalating bot tiers, varied combat game types, boss matches, and persistent ladder progress beside the original story.
- A unified demo library and player with pause, speed, stepping, rewind/fast-forward controls, honest legacy-format status, and full-world free-fly/player-follow playback for server-side multi-view recordings.
- Cross-platform support with Windows packages, directly executable Linux AppImages and archives for x86_64 plus preview aarch64, Steam Deck support on Linux, and experimental Apple Silicon/arm64 macOS OpenGL/Metal bridge packages through the signed/notarized DMG lane for credentialed release runs.
- Open development with releases, issue tracking, and community feedback all happening in public.
You need a legitimate Quake 4 install plus the openQ4 package that matches your operating system and CPU architecture.
| Tier | Practical target |
|---|---|
| Minimum | 64-bit CPU, 4 GB RAM, a working OpenGL compatibility driver with ARB2-era vertex/fragment program support, and about 12 GB free for the openQ4 package plus retail Quake 4 assets. Use the minimum or lowpower performance preset on constrained systems. |
| Recommended | Modern quad-core CPU, 8 GB RAM, OpenGL 4.1+ compatibility-class GPU with 2 GB+ VRAM, current graphics drivers, and 15 GB+ free. For high resolutions, quality, or ultra, 16 GB RAM and 6 GB+ VRAM gives much better headroom. |
Packaged support currently focuses on Windows, Linux x64, Steam Deck/SteamOS, preview Linux ARM64, and experimental Apple Silicon/arm64 macOS. Linux ARM64 requires a desktop OpenGL compatibility driver and remains preview until real-hardware Wayland gameplay, audio, and input signoff is accepted. See the Getting Started guide for the platform-specific requirements and caveats.
Bloom and HDR on mp/q4dm2 from the same loadscreen camera: normal rendering on the left, enhanced post-processing on the right.
Baked light-grid indirect diffuse on mp/q4dm2, shown off and on from the same loadscreen camera.
CRT post-processing on mp/q4dm8, shown off and on with a clean no-HUD camera.
A second CRT comparison on mp/q4dm6 shows the same post-process across a brighter indoor arena.
Renderer backends: OpenGL remains the default and recommended release renderer on every platform. The Vulkan backend is experimental and opt-in (r_renderApi vulkan, applied on engine restart), but now renders the stock Quake 4 material-program families, including environment and heat-haze effects, displacement and depth/blur post effects, and guide-driven parallax, custom-lighting, water, and refractive-glass stages. Vulkan also supports 4x MSAA with SMAA. On Windows and Linux it drives a Vulkan driver directly. Apple ships no Vulkan driver, so on experimental macOS the same module runs on top of MoltenVK, a Vulkan-on-Metal translation layer bundled inside both existing macOS packages — a runtime option rather than a third download, and not a Metal renderer. Broader parity and platform validation are still in progress, so visual artifacts or instability remain possible; an initialization failure falls back safely to OpenGL. See Display Settings → Renderer Backend.
- Install Quake 4 from Steam or GOG.
- Download the latest openQ4 build from the Releases page.
- On Linux, make the matching x86_64 or aarch64 AppImage executable and launch it; for an extracted archive, launch openQ4-client_<arch> (or openQ4-steamdeck on Steam Deck).
- If openQ4 does not find your Quake 4 install automatically, follow the path setup notes in the Getting Started guide.
Need the step-by-step version? Start with docs/user/getting-started.md.
- Getting Started - system requirements, installation, first launch, and common setup questions
- Client Settings Guide - where to find the most useful in-game settings
- Server Setup Guide - basic dedicated server setup and common server variables
- Display Settings - fullscreen, windowed mode, resolution scale, and multi-monitor behavior
- Input Settings - keyboard, mouse, controller, and binding help
- Gameplay Settings - gameplay and audio toggles for everyday play
- Arena Campaign (experimental) - single-player arena tiers, unlock rules, maps, game types, and bot rosters
- Steam Deck - launcher, controls, and Linux handheld notes
- Multiplayer Networking (experimental) - multiplayer tuning and lag-comp behavior
- Demo Library and Multi-View Demos - browse formats, use playback controls, and record or replay complete multiplayer matches
- Shadow Mapping - optional shadow-map settings and troubleshooting
- Light Grids - advanced lighting guide for players and testers
- Advanced Screen-Space Lighting (experimental) - bounded froxel volumetrics, SSR, SSGI, performance controls, and one-setting rollback
- Cel Shading - banded lighting and outline settings for the cel-shaded look
- DDS Texture Replacements - install and diagnose DXT/BC7 texture packs
- Level-Load Cache - learned preload and generated model, world, collision, and animation cache behavior, controls, rollback, and cleanup
- BUILDING.md - compile openQ4 from source
- TECHNICAL.md - advanced configuration, file layout, compatibility notes, and mod details
- Map Entity Strings - replace or extend a map's runtime entities without editing the original map
- openQ4 targets the official Quake 4 retail assets.
- It ships its own engine and game modules.
- It is not a drop-in runtime for the original proprietary Quake 4 DLL mods.
- The project is still in beta development, so compatibility work is ongoing.
Developers and testers should use the engine capability matrix for authoritative implemented/experimental/missing status, the idTech 5-level modernization roadmap for the compatibility-safe implementation order, the shared interaction-lighting contract, shared fog/blend contract, and shared material-deform contract for the default-off ownership and rollback boundaries, the loading/cache contract for the source-authoritative preload and generated-cache boundary plus pending evidence, and the stock-asset baseline for reproducible PK4, SP/MP, save/load, demo, log, and engine-screenshot evidence.
If you run into problems, please use the issue tracker and include crash logs or setup details when possible. For experimental macOS crashes, use the macOS support-data guide before filing or updating an issue.
Bug reports, compatibility reports, testing feedback, and code contributions are all welcome. If you want to help build the project itself, start with BUILDING.md. For details on how to report issues, submit changes, and follow project conventions, see CONTRIBUTING.md.
- themuffinator - openQ4 development and maintenance
- DarkMatter Productions - project stewardship and website
- Justin Marshall - Quake4Doom and early BSE reverse engineering reference work
- Robert Beckebans - renderer modernization reference work, including RBDOOM-3-BFG inspiration
- id Software's official Doom 3 and Doom 3 BFG source releases - retained idTech 4 source lineage; see the audited provenance inventory
- id Software and Raven Software - Quake 4 and the underlying technology
- Chris Robinson and the OpenAL Soft contributors - maintained cross-platform OpenAL runtime bundled by macOS packages
- akacross (Discord user) - Thorough playtesting on Linux and Windows, a huge help moving the project forward!
openQ4 engine code is licensed under the GNU General Public License v3.0. See LICENSE for details. Files retaining Doom 3 or Doom 3 BFG Edition headers also retain their upstream notices and are accompanied by the corresponding published Additional Terms; the source-provenance inventory records their scope, pinned audit references, and intermediate lineage without offering a legal conclusion.
The game-library code in openQ4-game is derived from the Quake 4 SDK and remains subject to id Software's SDK EULA. Quake 4 assets remain the property of id Software and ZeniMax Media.
openQ4 is an independent project and is not affiliated with, endorsed by, or sponsored by id Software, Raven Software, Bethesda, or ZeniMax Media.
Website | Repository | Game Library | Issues | Releases