The /visitors route for people who are new to you: the same rows, minus anyone already delivered to this project, at this tier, this UTC calendar month. Use it to pull a list repeatedly without paying for the same person twice.

Billing. A person is billed once per project, per tier, per UTC calendar month, the first time a new-only surface delivers them. The regular /visitors route bills every row it returns. People are billed after the response is delivered; a response that fails to send bills nothing and leaves those people new.

Request rules. project_id is required (a key bound to one project supplies it). kind must be buyers. pixel_id and dry_run return 400. All other parameters work as on /visitors, and rows come newest first.

Retries. Send an optional Idempotency-Key header, one value of 1 to 255 printable ASCII characters. A retry with the same key, project and tier returns the people the first attempt delivered again, counted in replayed, and bills nothing more for them. Use a new key for a new pull. A second request with a key whose first request is still running gets 409; retry once it completes. Without a key, every request is its own pull.

Long windows. A request that scans a very large window stops early. When has_partial_data is true and next_end_ms is present, everything from next_end_ms up to your end_ms was scanned; repeat the call with end_ms set to next_end_ms and the same start_ms to continue.

Availability. Enabled per account. When it is not enabled for yours, the route returns 404.