Bulk Create / Update Contacts
Upsert up to 1,000 contacts in a single call, processed asynchronously.
POST
Requires the
people:write scope. This endpoint accepts up to 1,000 contacts per call and processes them asynchronously — it returns immediately with an operation_id you can poll for completion. Like the single Create a Contact endpoint, contacts are keyed by email: any email that already exists is merged with the supplied data (there is no skip-existing mode).
Body
The contacts to create or merge (at least one, at most 1,000).
Response
Returns202 Accepted.
The id of the async operation.
The full URL of the operation — poll it to watch the batch progress from
pending → processing → succeeded.The operation’s initial status,
pending. Poll the operation to see it move as the batch is processed.The number of contacts accepted for processing.

