# Add suppression

> Suppress an address, e.g.

Source: https://sndr.sh/docs/api/suppressions/add-suppression

`POST https://api.sndr.sh/v1/suppressions`

Suppress an address, e.g. an opt-out collected outside SNDR. Returns 201; an address that is already suppressed keeps its original reason.

Scope: `send`

**Body** (JSON)

- `address` (string, required): Email address to suppress. Stored lowercase.
- `reason` (string): Why it is suppressed. Defaults to manual.
- `detail` (string): Optional note shown in the list.

**Request**

```bash
curl -X POST 'https://api.sndr.sh/v1/suppressions' \
  -H "Authorization: Bearer $SNDR_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{"address": "optout@example.com", "detail": "Unsubscribed via support ticket"}'
```

**Response** (201)

```json
{
  "address": "optout@example.com",
  "reason":  "manual"
}
```

**Errors**

- `unauthenticated` (401): Missing or invalid API key.
- `invalid_request` (400): Body is not valid JSON, or address is missing or not an email.
- `insufficient_scope` (403): The API key is missing the send scope.