It would be very useful to have email notification capability in Hashivault to be used when a secret like a token stored from a third party vendor be close to the expiration date
How would your Vault know that this secret is about to expire. I do not believe that this is possible from within the Vault.
That could be configured as part of the form or template of the secret. This is not new in this type of tools n the industry. For example “Cyberark” has this feature. Configure CPM Notifications | CyberArk Docs