Platform for letting guests book add-ons directly

[Diana Mulvihill]

Hi All ~ In a recent episode of Real Estate Rookie, Tony + Ashley referenced a platform that you can link to your hosting platform that will allow guests to book add-ons directly; they were advising someone who wanted to offer the option of daily passes to a local gym.

I'm actually needing/would love to have something like this, + didn't know that such platforms existed. Tony + Ashley said that there are several, they couldn't think of the names of them.

Does anyone know the names of any of these? Thank you!!