Create an apprenticeship master (or any external contact) and, optionally, attach them to a company of your school.

The email address must be free among the ACTIVE records of your school. A duplicate answers 409 EXTERNAL_ALREADY_EXISTS and hands back the id of the record already holding that address, under errors[0].context.existingExternalId — attach that one rather than creating a near-identical second. An ARCHIVED record also reserves its address: the answer is then 409 EXTERNAL_ARCHIVED_EXISTS with that record’s id under the same key, so the caller restores it (POST /externals/:id/restore) instead of creating a duplicate.

companyId must name a company of YOUR school; anything else answers 400 EXTERNAL_COMPANY_NOT_FOUND.