A pricing API for the Counter-Strike 2 market that provides real-time & historical data.
The market is distributed across a bunch of 3rd-party marketplaces, and there's no 'simple' API that provides genuinely high-quality data. It's been a super fun project, and I've been able to learn about collecting & managing a high (to me) scale of data, building an API from the ground-up, and creating my first 'commercial' website.