Update multiple leads that match a filter, applying the same changes to each.

When to use. Change many leads in one request. To update a single known lead, use PUT /leads/{id}.

Request body. A JSON object with two keys:

• where: the filter selecting which leads to update. Each key is a lead field, a scalar matches by equality and an array matches any of the listed values.
• update: the fields and new values to apply, optionally including a customFields object of your own field name and value pairs.

Returns. { "leads": [ ... ] } with the updated leads. If some values could not be applied, a messages array describes what was skipped.

Example. PUT /api/leads/mass-update with body { "where": { "id": [ 1, 2 ] }, "update": { "first_name": "John" } }