Customizing user invitation messages on a per user basis

Question

Fellow AWS devs,  
  
I have a question about modifying the invitation emails sent out by Cognito after creating users with the `adminCreateUser` method.  
For the email verification messages I managed to adjust the mails using a custom lambda method that is checking for
 `event.triggerSource === "CustomMessage_ForgotPassword"`
. I set this lambda to be triggered under triggers in the Cognito console under `Custom message` entry.  
  
When `adminCreateUser` is called for a new user, I do see the same lambda method being trigger, just this time with
 `event.triggerSource === "CustomMessage_AdminCreateUser"`
.  
But when I adjust the text with

```
    event.response.emailMessage = htmlBody;
```

, the email received is still the static text setup in the cognito console, not the modified one. Modifying the `response.emailMessage` for the verification mails works though.  
  
Whats the trick getting user-invitation emails modified?  
  
PS: the static email text in the cognito console is unfortunately not enough, as I have different clients using the same cognito pool and want to modify the emails on a per-client basis.  
  
Edited by: Bersaelor on Apr 29, 2020 3:59 PM

Answer

I figured it out myself:  
  
Since I hadn't adjusted the file with the html body being loaded, the
 `event.response.emailMessage = htmlBody`
 was being set with the verification email text in both cases.  
  
And the verification email text didn't contain a `{username}` placeholder. Once I had this placeholder in a proper user-welcome email the modified email was sent out instead of the static one in the cognito console. So, all solved.

Customizing user invitation messages on a per user basis

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