How to secure 3rd party API key with Auth0?

Serverless SPA needs to access a 3rd party API endpoint securely, using an API key.
How can I store API key in Auth0 and provide it to the client JS code only for logged in users?
API key is not specific to a user and it is same for all users. External API is used to log some simple data points (eg. Airtable, Sheets etc).
Is there a way to store app-scoped meta data using Auth0 ?