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The suppression list gives you a programmatic way to ensure that certain email addresses are never contacted through Leadterra, regardless of which campaign they appear in. This is useful for honoring unsubscribe requests received outside of Leadterra, removing known bad addresses from deliverability protection, or syncing opt-out data from a CRM or preference center. Once an address is suppressed, it is excluded from sending across your entire workspace — not just a single campaign.

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Endpoint

POST /v1/suppression-list

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Authorization

All requests must include a valid API key in the Authorization header as a Bearer token. 
Authorization: Bearer sk_live_YOUR_KEY

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Request Body

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emails
array
required
An array of email address strings to add to the suppression list. You may submit up to 1,000 addresses per request. Addresses that are already suppressed are silently ignored — they will not be counted in the suppressed response value and will not cause an error.

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Example Request

curl -X POST https://app.leadterra.co/v1/suppression-list \
  -H "Authorization: Bearer sk_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "emails": [
      "unsubscribed@example.com",
      "bounced@example.com"
    ]
  }'

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Response Fields

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suppressed
integer
The number of email addresses that were newly added to the suppression list in this request. Addresses that were already suppressed prior to this request are not counted.

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Example Response

{
  "suppressed": 2
}
Suppression is workspace-wide and cannot be undone via the API. Once an address is added to your suppression list it applies to all current and future campaigns across your entire workspace. There is no API endpoint to remove an address from the suppression list — removals must be performed manually through the Leadterra dashboard under Settings → Suppression List.

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Error Codes

CodeMeaning
400Bad Request — the request body is malformed, the emails field is missing, or the array is empty.
401Unauthorized — your API key is missing, invalid, or revoked.
404Not Found — the requested resource could not be located.
422Unprocessable Entity — one or more email addresses failed format validation. The response body will include an errors array identifying the invalid entries.