Doom in Browser

Updated Oct 13, 2026 · 2 more we checked and added

Doom has been ported to almost everything, so it is no surprise that it runs in a browser tab. The most interesting version right now is a WebAssembly build with online multiplayer, published as a Cloudflare experiment. It loads in about 5 MB and even works on phones.

For something heavier, d3wasm runs the Doom 3 demo on id Software's idTech 4 engine compiled to WebAssembly. Both are free and need no files.

Jump to: WebSockets Wasm Doom · Doom 3 Demo (d3wasm)

Two ways to play Doom in browser

There are two good ways to play Doom in browser right now, and they could hardly be more different.

WebSockets Wasm Doom is shareware Doom compiled to WebAssembly, with online multiplayer added. It loads in about 5 MB, starts almost instantly and works on phones as well as computers. This is the one to open if you just want to play.

The second is d3wasm, which runs the Doom 3 demo on id Software's idTech 4 engine in a tab. It is a download of about 380 MB and needs a desktop GPU, so think of it as a technical showcase rather than a quick game.

Multiplayer Doom on Cloudflare's edge

The WebAssembly Doom build was published as a Cloudflare experiment. Multiplayer runs on Cloudflare's network using Workers, WebSockets and Durable Objects, which is why you can start a match without anyone hosting a server.

From the start screen, choose Play Solo or Start Multiplayer. For multiplayer, start a room and share the link with friends.

Tab shows the map.
T opens chat.
F switches to fullscreen.
Left click or Space fires.
On phones, two virtual sticks handle moving and aiming.

The Doom 3 demo on idTech 4

d3wasm is derived from dhewm3, a community-maintained version of the GPL Doom 3 source code that id Software released. It runs the freely distributable Doom 3 demo, so you need no files of your own.

Two keys are remapped: press Home instead of Esc for the main menu, and Insert instead of the ` key for the console. Use a desktop with a dedicated or recent GPU, close other heavy tabs before you start, and give the first load time to finish.

Which Doom in browser should you pick?

On a phone, or with a slow connection: WebSockets Wasm Doom. It is about 5 MB and has touch sticks.
With friends: WebSockets Wasm Doom again. Start Multiplayer and share the room link.
On a strong desktop, out of curiosity: the Doom 3 demo. Budget time for the 380 MB download.
On an older laptop: stay with the original Doom. The Doom 3 demo is a heavy 3D game, even as a demo.

Why Doom runs everywhere

id Software released Doom in 1993 and published the game's source code in 1997. That decision is why Doom has been ported to calculators, cameras and nearly everything with a screen: anyone can compile the engine for a new platform.

The other half is the shareware episode. Doom was distributed as shareware, with the first episode free to copy and share, so a port can include it without asking you for files. Both builds on this page rely on that combination of open code and freely distributable data.

If you enjoy classic shooters, try Quake in browser, id's next game, or Return to Castle Wolfenstein in browser.

Tips before you play

Click into the game to capture the mouse. Press Esc to release it.
For multiplayer, start a room and send the link to friends.
The Doom 3 demo is a download of about 380 MB and needs a desktop GPU. Close other heavy tabs first.