Can I increase my API limit? What happens when I hit it?

Can I increase my API limit? What happens when I hit it?

I work for a company that runs a lot of services and we are moving towards using exclusively Zoho as our CRM of choice. That in mind, it might become possible the we reach 250 api calls per day when I need each form to check if a user is a member of a particular service by making an API call to their contact record. So my two questions are this:

Can I increase my API call per day limit?

and

What happens when I hit the limit of my API calls?

Forever yours,
Gabe

P.S. Bonus points if someone informs me if this API limit is per user per day.

P.S.S Bonus bonus points if someone tells me if 3rd party integrations of Zoho (for example, jotform) record updates/creations are deducted from my daily limit

P.S.S.S. Bonus bonus bonus points if someone actually answers.