Q3Edit: Browser-based level editor for Quake 3 maps with WebAssembly playback

What it does

Q3Edit is a browser-based level editor for Quake 3 that lets creators build, compile, and playtest maps without installing software. The editor supports brush and patch geometry, constructive solid geometry (CSG), terrain sculpting, and entity placement in a four-view layout similar to id Radiant. Maps are saved as standard .map files. Compilation runs locally using q3map ported to WebAssembly, and playback happens in-browser via a WebAssembly build of ioquake3. The tool ships with OpenArena assets and requires WebGL2.

Who it is for

Level designers for Quake 3 Arena and custom mods who want to avoid installing a desktop editor or game engine. The editor also integrates with AI coding agents through Model Context Protocol (MCP), allowing users to connect Anthropic's Codex or Claude to inspect, modify, and validate geometry while viewing live edits. This appeals to creators interested in AI-assisted map authoring.

Pricing

The site does not show prices. The project appears open-source and the editor itself is free to use in the browser.

How it stands out

Running entirely in a browser eliminates setup friction. Most Quake 3 mapping requires GtkRadiant or NetRadiant downloaded and configured locally. Q3Edit removes that barrier and embeds the full pipeline—editing, compilation, and playback—in a single tab. The MCP integration for AI-assisted authoring is novel in game level editing; the system lets AI agents make atomic edits visible in real-time with full undo support. Keeping assets, compilers, and activity logs local addresses privacy concerns some creators have with browser-based tools.

What a founder should check

Any competitor should verify switching costs from existing tools. Designers with years of keyboard shortcuts and muscle memory in Radiant or NetRadiant may resist learning a new interface, even if it's more convenient. Test whether the performance and feature completeness of this WASM-based editor match or exceed the desktop incumbents for complex maps with high brush counts and intricate geometry.

Second, validate the durability of the moat. The real barriers are Radiant-style UI familiarity and integrations like MCP support. A competitor could fork the same ioquake3 and q3map WASM binaries. The differentiation rests on UX, community adoption, and ecosystem depth—whether MCP integration becomes a standard expectation and whether the tool attracts enough creators to justify ongoing maintenance.

Third, test the practical limits of in-browser tools. Compile times, memory constraints on large maps, and browser stability under heavy WebGL2 rendering should all be benchmarked against desktop rivals to ensure the convenience trade-off is worthwhile.

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