Hi I search some free game to speedrun with a active community Do you have some suggestion ?

Google minesweeper. This one's not really a Speedrun, more just luck though. Cookie clicker is also a good one.

Here's a list of all the most popular web games for speedrunning right now: https://www.speedrun.com/games#platform=Web&orderby=mostactive&unofficial=off Pick one of these and you're basically guranteed to find a game with an active community.

Of the top 50 active web games right now, I personally recommend .S, Grey-Box Testing, Celeste Classic 2, and Choppy Orc.