URL: /code/apps/mailboxes/suppress · Id: `page:/code/apps/mailboxes/suppress`

# Contact.suppress

> Adds an address to the one list every send reads first, honored by every startup, forever.

POST https://api.sb/{your-domain}/contacts/{contact}/suppress

Adds an address to the one list every send reads first, honored by every [startup](https://startupbuilder.dev/business/nouns/startup), forever.

- **Action class:** None
- **Approval:** Runs on its own
- **Emits:** `Contact.suppressed`
- **Price:** Free

```text title="Run it · Ask"
The Crestline leasing inbox bounced hard: never send to it again.
```

```ts title="Run it · SDK"
import { $ } from 'startup-builder'

const result = await $.try.Contact.suppress({ contact: 'https://api.sb/leaseline.app/contacts/contact_Le4sC1nR7r' })
```

```json title="Run it · Response"
{
  "api": "https://api.sb/leaseline.app",
  "contact": {
    "$id": "https://api.sb/leaseline.app/contacts/contact_Le4sC1nR7r",
    "$type": "Contact",
    "email": "leasing@crestline-residential.com",
    "suppressed": true
  },
  "action": {
    "operation": "Contact.suppress",
    "mode": "try",
    "status": "done"
  }
}
```

Its Inputs, Outputs, Effects and guards quote [the hub’s `Contact.suppress`](https://startupbuilder.dev/business/nouns/contact/suppress); this page adds what each Venue honors, its limits and a worked call. It is one of the [Verbs](https://startupbuilder.dev/business/nouns/verb) of [Mailboxes](/code/apps/mailboxes#verbs).

## Inputs
| Name | Type | Default | Meaning |
| --- | --- | --- | --- |
| `contact` | `Contact` | Required | The Contact who opts out. |

## Outputs
| Field | Type | What `null` means |
| --- | --- | --- |
| `contact` | `Contact` | Never null: the suppressed Contact. |

## Effects
**Action class**

None: no approval rule names it, so it runs within its seat’s Permissions and Limits

**Modes**

- `try`: Runs every check and returns the record as it would be; nothing is stored.
- `send`: Returns a pending Action at once; `Contact.suppressed` fires when it is done.
- `do`: Waits for the Action to finish and returns the record.

**Idempotency**

Only with a key: the same `Idempotency-Key` and input return the first Action, and the same key with other input returns `409`.

**Saved or shared**

Ends every Sequence the Contact is in. Keeps the record: suppression is a row, never a delete.

**Emits**

`Contact.suppressed` with `{ contact }`

**Performed by**

Whichever seat calls it

**Price**

Free on your own account: the platform charges nothing for the call.

## On each Venue
It acts on your own records and reaches no Venue, so every account answers the same way.

## What try does
Runs every check the call meets and returns the record as it would be; nothing is stored, sent or posted.

## Refuses when
The hub sets no guard of its own on this call: it refuses only on the shared checks every write meets (a missing record, a Permission the seat lacks).

## When it waits
Returns in one response; nothing waits.

## Example
In `send` mode the call returns its pending Action at once, and `Contact.suppressed` delivers the result.

**Ask**

```text
The Crestline leasing inbox bounced hard: never send to it again.
```

**API**

```bash
curl -X POST "https://api.sb/leaseline.app/contacts/contact_Le4sC1nR7r/suppress?mode=send" \
  -H "Authorization: Bearer $SB_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{}'
```

**CLI**

```bash
npx startup-builder do Contact.suppress --send --data '{}'
```

`--send` returns the pending Action at once.

**MCP**

```json
{
  "name": "do",
  "arguments": {
    "mode": "send",
    "code": "return await $.Contact.suppress({})"
  }
}
```

**SDK**

```ts
import { $ } from 'startup-builder'

const result = await $.send.Contact.suppress({
  contact: 'https://api.sb/leaseline.app/contacts/contact_Le4sC1nR7r',
})
```


```json title="Response, in send mode"
{
  "mode": "send",
  "action": {
    "$id": "https://api.sb/leaseline.app/actions/action_Sd3kQ9vT2w",
    "operation": "Contact.suppress",
    "status": "pending",
    "reason": "running"
  }
}
```

To retry, send the same `Idempotency-Key`: the retry returns the first answer for $0. A new key reads again.

## Used by
- **Workflows:** [List refresh](/capabilities/find-customers/list-refresh)
- **Jobs:** [Reach out](/capabilities/reach-out)

## Related
[`Message.broadcast`](/code/apps/mailboxes/broadcast) · [`Message.schedule`](/code/apps/mailboxes/schedule) · [`Mailbox.warm`](/code/apps/mailboxes/warm) · [`Mailbox.rest`](/code/apps/mailboxes/rest) · [`Domain.authenticate`](/code/apps/mailboxes/authenticate) · [`Mailbox.retire`](/code/apps/mailboxes/retire) · [`Contact.unsubscribe`](/code/apps/mailboxes/unsubscribe) · [`Consent.withdraw`](/code/apps/mailboxes/withdraw)