Firestore Customer-Managed Encryption Keys (CMEK) is generally available (GA) behind an allow-list. Please fill out the form to get access to this feature. We'll try to respond to you in 1-2 business days. You can reach out to
firestore-cmek-feedback@google.com for any additional question.
Please be aware of the following when using CMEK and/or requesting access to this feature: 1) There are a limited number of CMEK databases available 2) Firestore may remove customers ability to create new CMEK databases to limit the number of CMEK databases, based on volume