in order to test the API - I need to log in using the API key. Where can I enter this key when creating an API autotest?

Cypress supports authorization headers in their request operation 🙂 Check https://docs.cypress.io/api/commands/request and as an example https://medium.com/@kbalaji.kks/api-testing-with-cypress-authorization-bearer-token-saving-and-invoking-the-token-values-3e3d95b86298 Hope i could help!