CUBA Platform can be configured to lock records when they are edited using a CUBA Application. How can one do the same thing but using REST API to request a lock on an object that the user is editing via the API?
There are no methods for pessimistic locks management in the standard REST API. You’ll have to write you own REST controller with methods for locking and unlocking objects. Use com.haulmont.cuba.core.app.LockService for that.