Using Knack API in Zapier

Hi there - this is a question from a very non-technical person so please do excuse me. I've built a database in Knack which is used by external companies. I'd like to give them access to the api in Zapier so that they can pull the data into Salesforce, Mailchimp etc. This seems doable, but the problem is that it's also sending requests the other way. So if a user is making changes in salesforce they can send this back to the knack database. I need to maintain complete control over the core data we hold.

My question is if there's a way to make the api pull only so that end users can't make changes, but still benefit from all the integration benefits of Zapier?

Thanks in advance if anyone does have the answer!