Automating Badge Assignment for Beta Testers in Slack

Question about programmatically adding badges in Slack for our beta testing program - We want to automatically tag users and give them a badge in Slack when they join the beta group in our backend. Currently doing this manually, but we're building UI controls to let users opt in/out. We're calling it our Guinea Pig program and planning to give participants special badges plus some swag (t-shirts, stickers, hats) when they join. Is there a straightforward way to do this?