List the companies of your school, most recently created first. search matches a literal substring of name, displayName or businessIdentifier; businessIdentifier is an exact match. To find companies by your own references, use POST /companies:search with filters.externalReferenceIds.

includeStudents and includeExternals add the full, unpaginated students and externals arrays to each company: active people only; learners attached directly or through an apprenticeship contract, each once; external contacts counted once per email, the ones without an email left out. Learners are ordered by last name, first name, then ID; external contacts by last name, first name, then email. Each array is empty when nobody is attached.

Several learners and external contacts can be attached to one company, and a change to the company applies to all of them.

Attach a learner with companyId on PATCH /students/{id} (or its by-reference-id twin): it is the "Company" field of the learner record in the School app. That call also copies the company display name into the learner's historical company text; updating the company later does not rewrite that text.