What is the ruling on establishing and dealing with crowdfunding websites that allow creators to raise capital for their projects by offering rewards to contributors, with the website receiving a percentage of the total amount collected?

There is no legal impediment to what was mentioned regarding the project owner's offer on the website, specifying the value of the services for those who wish to participate, and his receiving compensation upon the project's establishment, or the return of his subscription amount if it is not completed.

As for the website's commission being a percentage of what is collected, there is a difference of opinion. Sheikh Al-Islam (Ibn Taymiyyah) holds the view that it is permissible if the compensation for the work is a common share of what is obtained. According to this view, there is no impediment for the website to take a percentage in exchange for displaying the project, collecting the funds, and transferring them.