Equilibrium decisions for an innovation crowdsourcing platform

•We derived the equilibrium between the three stakeholders in a crowdsourcing platform.•We derived the equilibrium effort-spending strategy of participants in various innovation contests.•We proved that it is always optimal for a firm to use the single-prize mechanism when it crowdsources its innovation task.•We showed it is better for the platform to use the fixed intermediary fee schedule rather than the proportional one.