### Solution
> After discussion with charles & weiko, we chose the long term
solution.
>
> Fix FE to request checkUserExists resolver with lowercased emails
> Add a decorator on User (and AppToken for invitation), to lowercase
email at user (appToken) creation. ⚠️ It works for TypeOrm .save method
only (there is no user email update in codebase, but in future it
could..)
> Add email lowercasing logic in external auth controller
> Fix FE to request sendInvitations resolver with lowercased emails
> Add migration command to lowercase all existing user emails and
invitation emails
> For other BE resolvers, we let them permissive. For example, if you
made a request on CheckUserExists resolver with uppercased email, you
will not found any user. We will not transform input before checking for
existence.
[link to comment
](https://github.com/twentyhq/twenty/pull/12130#discussion_r2098062093)
### Test 🚧
- sign-in and up from main subdomain and workspace sub domain > Google
Auth (lowercased email) ✔️ | Microsoft Auth (uppercased email ✔️ &
lowercased email) | LoginPassword (uppercased email ✔️& lowercased
email✔️)
- invite flow with uppercased and lowercased ✔️
- migration command + sign-in ( former uppercased microsoft email ✔️) /
sign-up ( former uppercased invited email ✔️)
closes https://github.com/twentyhq/private-issues/issues/278, closes
https://github.com/twentyhq/private-issues/issues/275, closes
https://github.com/twentyhq/private-issues/issues/279
7461b7ac58