How does a game run in a browser tab?
A browser port takes the game’s original source code, or a rebuilt version of it, and compiles it to WebAssembly. WebAssembly is a compact program format that every modern browser runs at close to native speed. A toolchain such as Emscripten does that compiling and replaces the game’s PC or console functions with web ones. Graphics go through WebGL or the newer WebGPU, sound through the browser’s audio system, and controls through the keyboard, touch or gamepad.
When you open the page, the browser downloads the game’s code and files, often hundreds of megabytes. It keeps them in its storage, so the next start is faster. From then on the game runs on your own processor and graphics chip, just like an installed game.
Where does the code for a browser port come from?
Browser ports need the game’s code in a form they can compile. It usually comes from one of three places:
| Source of the code | What it means | Example |
|---|---|---|
| Released source code | The developer published the engine’s code | Many classic first-person shooters |
| A community decompilation or reverse engineering | Fans rebuilt the code | GTA Vice City and GTA III web builds based on reVC and re3 |
| A port of an existing PC version | The PC code was adapted for the web | The Half-Life 2 web port, built on an earlier Portal web port |
The source of the code also decides the legal risk. Ports that ship a commercial game’s art and music without the player’s own files are the ones publishers take down most often.
Why do some browser ports need my own game files?
A browser port’s code may be free to share, but the game’s graphics, levels and music belong to the publisher. Ports that respect that ask you for files from a copy you own. The GTA Vice City web build, for example, asks you to upload a file from your original game. A Halo: Combat Evolved web port asked for a disc image made from the player’s own Xbox copy. Ports that “just work” with no files usually bundle the publisher’s assets, which carries more risk of a takedown.
Browser port vs cloud gaming: what’s the difference?
A browser port runs on your device. Cloud gaming, such as Xbox Cloud Gaming or GeForce NOW, runs the game on a remote server and streams video to your browser. Cloud gaming needs a fast, steady connection and usually a subscription and a copy of the game on that service. A browser port needs a one-time download and a capable device, and it can keep working offline once its files are stored.
How well do browser ports run?
Better than most people expect. Reviewers reported over 100 fps for the Half-Life 2 web port on desktop hardware. Big ports still need a recent browser and a good amount of memory. Phones are the weak spot: they give each tab much less memory than a PC, so large ports often fail there. Each of our port pages shows how the port ran on every device we tested, with load times and download sizes.
Can browser ports have multiplayer?
Yes, when the port includes its own servers. Underground 2 Revived, a browser port of Need for Speed: Underground 2, launched in late October 2026 with online free roam and a downloadable game size of about 1.4 GB. Multiplayer in a browser port depends on the project keeping its servers online, so it can stop without warning.
Do browser ports save my progress?
Most browser ports save to your browser’s storage on your device. That means your progress stays in that one browser on that one device. Clearing your browsing data for the site deletes it, and a private window forgets it when you close the window. Some ports let you export saves: the Vice City web build, for example, has a save manager that imports and backs up save files. Check a port’s page for how it saves before you play for hours.
Do browser ports work on a Chromebook or iPhone?
Many do on a Chromebook, because it runs the same Chrome as a Windows PC, just often with a weaker processor. iPhones are harder: every iPhone browser outside the EU uses Safari’s engine, and Safari limits memory per tab, so big ports often stop while loading. Smaller ports usually work everywhere. Our device tests show the result for each.
Are browser ports safe?
The browser itself keeps a port in a sandbox, so a web page can’t install programs on your PC. The risks are around the game: sites that copy a port and add pop-ups, fake download buttons or notification prompts. Play a port only on its official page, and read how to spot fake downloads. Our port pages show a safety check of each host, with the date we checked it.
Why do browser ports get taken down?
Most takedowns happen because a port shipped a commercial game’s files. Publishers can send a DMCA notice to the host, and the port disappears, sometimes within hours of going viral. Ports that require your own files and contain only their own code stay online far more often. Our takedowns log lists every removal we know of.
How do I find browser ports that work?
Our browser ports list collects every port we track, with its status, what it needs and the date of our last test. Start there, and check the port’s page before you play.