So does this mean that you can use it for all your small open source repos or do you need to apply for each one? The only mention of free offering is in pricing page where you fill a form with a repo link to apply for the free offering.

Edit: found the information in docs here [2]

[2] https://docs.greptile.com/pricing

That form is if you want to install the code review bot or other GitHub integrations for free on your repo .

If you want to chat with your repo for free you can do that on the website, assuming it’s a small public repo.