My task is to create an LWC component and then add it to a managed package. I was told that to store the API and the key to it, you should use Custom Settings and Custom Metadata Types. No more specifics. Since I'm new, I assumed that the API should be stored in Custom Settings, and the key in Custom Metadata Types.

I added a new entry in Custom Settings: enter image description here

Next, I try to add a new field and get an error. I understand that this is not how I write the path to my Custom Metadata Types record? Here is my formula:

"the_api_is_specified_here" + $CustomMetadata.Weather_api_key__mdt.key__c

enter image description here

In here is my Custom Metadata Types record (which I am trying to refer to at the end of the formula):

enter image description here enter image description here

Maybe I'm wrong and I need to implement it in a different way?

  • Something does not seem to match up. You separately show $CustomMetadata.Weather_api_key__mdt.key__c as part of your formula, but the error shown in your screenshot seems to indicate that you have $CustomMetadata.Type__mdt.Weather_api_key.key__c in your formula. Could you please clarify?
    – Moonpie
    Apr 28, 2021 at 15:12

1 Answer 1


You are mixing CustomSettings and CustomMetadataType in your setup. It looks as if you wish to use CustomMetadataType and I recommend that.

Your formula to retrieve the key__c from Weather_api_key (CustomMetadataType) should be:


Your formula to retrieve the key__c from weatherAPI__c (CustomSetting) should be:

  • I was confused and thought the same thing at first, but I believe the OP might be trying to reference a Custom Metadata Type in a formula on a field inside of a Custom Setting.
    – Moonpie
    Apr 28, 2021 at 16:29
  • @Moonpie I updated the screenshot with the error and described the essence of the issue in more detail. Apr 28, 2021 at 17:28
  • Are you looking to use the Custom Metadata Type record as a Default Value on the new field in a Custom Setting? Formula Data Type field is not supported in Custom Setting so if you are picking this Data Type as the new field, your not creating it on a Custom Setting.
    – TSmith
    Apr 29, 2021 at 11:39

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