REST: Updating Multiple Resources With One Request – Is it standard or to be avoided?

You could PATCH the collection, e.g.

PATCH /items
[ { id: 1, name: 'foo' }, { id: 2, name: 'bar' } ]

Technically PATCH would identify the record in the URL (ie PATCH /items/1 and not in the request body, but this seems like a good pragmatic solution.

To support deleting, creating, and updating in a single call, that’s not really supported by standard REST conventions. One possibility is a special “batch” service that lets you assemble calls together:

POST /batch
[
  { method: 'POST', path: '/items', body: { title: 'foo' } },
  { method: 'DELETE', path: '/items/bar' }
]

which returns a response with status codes for each embedded requests:

[ 200, 403 ]

Not really standard, but I’ve done it and it works.