Job openings or internships can be posted at job portals such as Dutch Startup Jobs or tech IT job board Dice. Vacancies specific to internationals are re-directed to I Amsterdam’s job board; you can find out how to directly add your vacancy here. Universities such as UvA and VU have study-specific job boards; you can explore opportunities by contacting their service desks.
Among the Dutch workforce, LinkedIn is a highly used platform that should not be underestimated in your recruitment process. You should have a company page on LinkedIn where you post vacancies and updates about your company and work environment to create engagement with your potential workforce (take inspiration from Amsterdam scale-up Travelbird, which has over 13,000 followers on LinkedIn).