is it possible to run pygame or pyglet in a browser?

Neither pyglet nor pygame will run in a browser. I wouldn't really recommend using Python at all if you target is a web browser. JavaScript (with HTML5 Canvas), Flash, or Java applets are is better suited for that environment.

If you're dedicated to the idea of using Python, there are a number of projects that can compile Python into JavaScript. There are some mentioned on the Python wiki. Here are a few:

• Skulpt
• Pyjamas
• Pyjaco

You'll need to write your own graphics and audio systems, though, since none of those projects can convert the native code needed by pyglet and pygame into JavaScript.

Today, I'd recommand using pygbag from https://pygame-web.github.io. It uses the same principles from Panda3D webgl port (not the old plugin) using Web Assembly for modern browsers.

Installation: pip3 install pygbag

Usage: python3 -m pygbag your_game_folder/main.py

With pygbag tool you can host/run/package directly your pygame-ce/panda3D desktop project in all modern browsers (and Safari iOS≥15).

It is already widely adopted for 2D game jams and you can also start 3D projects.

You can also use pygame-ce wasm in REPLit with pygbag to get a performance gain (people using it said it makes a big difference). For that see https://github.com/pygame-web/pygbag/issues/110.

It requires a bit of reprogramming, but i made a pygame library "port" to the browser/nodewebkit using Brython and GameJS. You can program using a version of pygame and python 3 in the browser. You can check it out at https://github.com/asherwunk/pygjs

Another option to run pygame in a browser is to use pygbag. Install pygbag with pip install pygbag

pip install pygbag

Put the code in a file named main.py and adapt your pygame code like this:

import pygame
import asyncio

pygame.init()

# initializations: pygame.display.set_mode, ...
# [...]

def main():

    run = True
    while run:

        # application loop: pygame.event.get(), pygame.display.flip(), ...
        # [...]

        await asyncio.sleep(0)
        
asyncio.run(main())

Build the project with the command:

pygbag .

Minimal example:

Live demo

import pygame
import asyncio

pygame.init()
window = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()

rect = pygame.Rect(0, 0, 20, 20)
rect.center = window.get_rect().center
vel = 5

async def main():
    run = True
    while run:
        clock.tick(60)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False
            if event.type == pygame.KEYDOWN:
                print(pygame.key.name(event.key))

        keys = pygame.key.get_pressed()
        
        rect.x += (keys[pygame.K_RIGHT] - keys[pygame.K_LEFT]) * vel
        rect.y += (keys[pygame.K_DOWN] - keys[pygame.K_UP]) * vel
            
        rect.centerx = rect.centerx % window.get_width()
        rect.centery = rect.centery % window.get_height()

        window.fill(0)
        pygame.draw.rect(window, "red", rect)
        pygame.display.flip()
        await asyncio.sleep(0)

    pygame.quit()
    exit()

asyncio.run(main())

An option is to use repl.it. It allows creating Python/PyGame scripts and multiplayer coding. When creating a new repl, select the Pygame template:

Example: repl.it/@Rabbid76/PyGame-TransparentShapes