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Every response from the ENS Ads API uses a standard JSON envelope. Successful responses always include a "status": "success" field alongside the relevant data. Error responses always include "status": "error" and a message field describing the problem. Inspect the HTTP status code first, then read the message field for details when handling errors in your integration.

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Status codes

CodeStatusDescription
200OKThe request was successful. The response body contains the requested data or a confirmation message.
400Bad RequestThe request is missing a required parameter or contains an invalid value. Check the message field for specifics.
401UnauthorizedThe Authorization header is missing or the API key is invalid. Verify your credentials and that the header is formatted correctly.
404Not FoundThe requested resource does not exist. Verify the endpoint path and any IDs in your request.
429Too Many RequestsYou have exceeded the API rate limit. Back off and retry after a short delay. See Rate Limits for guidance.
500Internal Server ErrorAn unexpected error occurred on the server. If this persists, contact ENS Ads support.

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Success response format

All successful responses follow this envelope structure: 
{
  "status": "success",
  ...
}
For the Fetch Campaigns endpoint, the envelope includes a data array and a count: 
{
  "status": "success",
  "data": [ ... ],
  "count": 1
}
For tracking endpoints (impression and click), the envelope includes a message confirmation: 
{
  "status": "success",
  "message": "Impression tracked successfully"
}

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Error response format

All error responses include "status": "error" and a message field. The message value provides a human-readable description of what went wrong.

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400 — Bad Request

Returned when a required parameter is absent or a value fails validation. 
{
  "status": "error",
  "message": "placement parameter is required"
}

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401 — Unauthorized

Returned when the Authorization header is missing or the supplied API key is not recognized. 
{
  "status": "error",
  "message": "unauthorized"
}

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429 — Too Many Requests

Returned when your integration exceeds the allowed request rate. Implement exponential backoff and retry logic to handle this gracefully. See Rate Limits for recommended strategies. 
{
  "status": "error",
  "message": "Rate limit exceeded"
}