Hi @oli! 
I had a look at the API documentation for Google Calendar here and I’m not seeing any options available to allow access to be set to Open. So it looks like this wouldn’t be possible to until Google add that functionality to their API.
However, I did some further digging and it looks like the default settings can be changed by the IT administrator for your organization:

Hope that helps to get you pointed in the right direction. If you run into any issues or have further questions just let us know! 
That’s super helpful Sam, thank you! Kind of wild how limited Google Calendar’s API is
In case it’s useful for future people:
- We’re scoping out the above solution as it’s definitely the simplest, hopefully our IT admin can make it work
- The backup solution is we basically create the calendar invites and then manually update them (not much of a solution)
- We also looked at whereby.com which allows to generate open meeting rooms via API. I don’t really want to do this as it introduces more technical complexity, but it’s good to know that it’s an option as the number of calendar invites grows
You’re very welcome, @oli! So glad my reply was helpful to you 
Thanks for sharing details of your plan, I’m sure it will be super useful to others that might come across this in the future! I’ll go ahead and mark it as the best answer since you appear to have all the bases covered here.
Let u know if you need anything else. In the meantime, hope you have a great weekend! 
Hey! Unfortunately, Zapier doesn’t currently support modifying Google Meet access settings like “host must join first” or setting the meeting to “Open” automatically.
These options can only be adjusted manually in the Google Meet or Calendar UI, and Google hasn’t exposed those specific controls through their Calendar API yet — so no automation tool (including Zapier) can handle that part for now.
A possible workaround is using a Google Workspace Admin tool or script, but it would require custom coding. Let me know if you’d like to explore that route!
Thanks @Adil Waqas - will let you know if we can’t get it working in house!