There is Retool API in Settings > API. However, I haven't tried that myself so not sure how to set it up.
As an alternative though, since the use case here is for user validation / approval, I think you might benefit from the User Tasks feature of Retool Workflows. It is still in private beta but my company signed up and we've used it quite successfully in our systems. You can also sign-up here: Early Access: Add user-driven steps, tasks, and approvals to automations in Retool
Might be a more complicated solution but this sounds like a great use case for the user task feature.