Overview

BZFlag (an abbreviation for Battle Zone capture the Flag) is a free and open-source online multiplayer 3D tank battle game. You drive a tank from a first-person view across a server-defined 3D world, hunting enemy tanks and fighting for team flags. The project started in 1992 as a student project by Chris Schoeneman at Cornell University, drew inspiration from the classic Battlezone, and has been continuously developed and played ever since — it was the SourceForge Project of the Month in April 2004 and remains one of the oldest active open-source games. The current stable release is 2.4.30 “All Is Clear” (March 2025).

Key Features

• First-person 3D tank combat — rendered in OpenGL with SDL for cross-platform input and audio, giving smooth, tactical tank-vs-tank shooting across low-poly 3D maps.
• Online multiplayer at large — an official public server list on bzflag.org and typically around 250 servers live at once; join any server directly from an in-game browser.
• Four gameplay styles — free-for-all (FFA), capture-the-flag (CTF), open free-for-all (OFFA) and rabbit chase, with the game mode chosen by the server host.
• Super flags — pick up good and bad flags that buff or handicap your tank: rapid fire, guided missiles, lasers, high speed, shockwave and more, one or two-letter codes shown on the scoreboard.
• Teams, rogues and observers — join the red, green, blue or purple team, play solo as a rogue, or spectate as an invisible observer.
• Customisable worlds — the text-based .bzw map format places boxes, pyramids, teleporters, cones, arcs, cylinders, spheres and team bases; build maps in Blender, Wings 3D or the older BZEdit editor.
• Living server environments — servers can simulate time of day, weather, rain, snow, slippery ground, altered gravity and fog, changing how each match plays.
• Anti-cheat and moderation — kill thresholds, message filters and server-side kicking tools keep public servers fair, and the often playful custom maps and chat keep it friendly.

Why Use It

BZFlag delivers fast, social, genuinely fun arena combat entirely for free — no ads, no in-app purchases, no accounts and no telemetry. It has a long heritage (over two decades of continuous development), a small but dedicated community, and a low system footprint that runs happily on modest hardware. Because the source is open, you can also host your own server for friends or a LAN party, or mod the client and maps as much as you like. It is well suited to younger players and casual sessions, while still offering depth for competitive tank vets.

Use Cases

• Quick, competitive multiplayer tank battles on public BZFlag servers — free-for-all or capture-the-flag.
• Hosting your own server for friends, a LAN party, or a closed community match with custom rules and maps.
• Designing custom worlds, flags and environments with the .bzw map format and Blender/3D modelling tools.
• Running a lightweight, family-friendly multiplayer game on an older or low-power machine.

Platforms

Windows · macOS · Linux · FreeBSD (the game originally ran on SGI IRIX workstations).

Licence

Free and open source under a dual LGPL-2.1 and MPL-2.0 licence: you may redistribute and modify the game under either set of terms, and project binaries may link against LGPL and MPL code. There are no ads, no in-app purchases and no accounts.

Similar Open-Source Games

• Xonotic — a fast, free and open-source arena first-person shooter with a similar pick-up-and-join ethos.
• Warzone 2100 — if you prefer tank-heavy real-time strategy, this open-source classic is all about armoured vehicles and base building.

Website

bzflag.org · source code on GitHub

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