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Call this endpoint each time you display a campaign to a user. An impression event tells the ENS Ads platform that a specific campaign was rendered in your application, which allows advertisers to measure reach and delivery. You should fire this request immediately after a campaign becomes visible to the user — not before rendering, and not after a click.
This endpoint must be called from your server. Your API key must never appear in client-side or user-facing code. Route impression events through your backend to keep your credentials secure.

Endpoint

Content-Type: application/json

Request example

Body parameters

integer
required
The unique ID of the campaign that was displayed. Use the id field returned by the Fetch Campaigns endpoint.
string
required
The placement ID where the campaign was rendered (e.g., header_banner, article_inline). This must match the placement you used when fetching the campaign.
string
The ISO 3166-1 alpha-2 country code of the user’s geographic location (e.g., US, GB, FR). Including this improves reporting accuracy for advertisers.
string
The device type of the user viewing the campaign. Accepted values: mobile, desktop, tablet.

Response

200 — Success

400 — Bad Request

Returned when a required field is missing from the request body.

401 — Unauthorized

Returned when the Authorization header is missing or the API key is invalid.
Call this endpoint exactly once per display event per user. Sending duplicate impression events for the same campaign view inflates delivery metrics and violates the platform’s usage terms. Do not call it in polling loops, on re-renders, or more than once per page load for a given campaign.