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

# Mailbox.rest

> Pauses a Mailbox’s sending when a brake fires, such as bounces over 2%, and resumes it when the reading clears.

POST https://api.sb/{your-domain}/mailboxes/{mailbox}/rest

Pauses a [Mailbox](https://startupbuilder.dev/business/nouns/mailbox)’s sending when a brake fires, such as bounces over 2%, and resumes it when the reading clears.

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

```text title="Run it · Ask"
Bounces hit 3% this morning: rest dana@tryleaseline.app.
```

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

const result = await $.try.Mailbox.rest({ mailbox: 'https://api.sb/leaseline.app/mailboxes/mailbox_Tq3wE7rY1u', reason: 'Bounces 3.1% over the last 200 sends.' })
```

```json title="Run it · Response"
{
  "api": "https://api.sb/leaseline.app",
  "mailbox": {
    "$id": "https://api.sb/leaseline.app/mailboxes/mailbox_Tq3wE7rY1u",
    "$type": "Mailbox",
    "address": "dana@tryleaseline.app",
    "state": "resting"
  },
  "action": {
    "operation": "Mailbox.rest",
    "mode": "try",
    "status": "done"
  }
}
```

Its Inputs, Outputs, Effects and guards quote [the hub’s `Mailbox.rest`](https://startupbuilder.dev/business/nouns/mailbox/rest); 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 |
| --- | --- | --- | --- |
| `mailbox` | `Mailbox` | Required | The Mailbox to pause. |
| `reason` | `string` | Required | The brake that fired. |

## Outputs
| Field | Type | What `null` means |
| --- | --- | --- |
| `mailbox` | `Mailbox` | Never null: the Mailbox, resting. |

## 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; `Mailbox.rested` 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**

Fires on its own above 0.1 percent complaints or 2 percent bounces; a brake never waits. A blocklisted Domain also opens an Incident.

**Emits**

`Mailbox.rested` with `{ mailbox }`

**Performed by**

[Customer lead](https://startupbuilder.dev/agents/customer/customer-lead)

**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 `Mailbox.rested` delivers the result.

**Ask**

```text
Bounces hit 3% this morning: rest dana@tryleaseline.app.
```

**API**

```bash
curl -X POST "https://api.sb/leaseline.app/mailboxes/mailbox_Tq3wE7rY1u/rest?mode=send" \
  -H "Authorization: Bearer $SB_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
  "reason": "Bounces 3.1% over the last 200 sends."
}'
```

**CLI**

```bash
npx startup-builder do Mailbox.rest --send --data '{
  "reason": "Bounces 3.1% over the last 200 sends."
}'
```

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

**MCP**

```json
{
  "name": "do",
  "arguments": {
    "mode": "send",
    "code": "return await $.Mailbox.rest({ reason: 'Bounces 3.1% over the last 200 sends.' })"
  }
}
```

**SDK**

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

const result = await $.send.Mailbox.rest({
  mailbox: 'https://api.sb/leaseline.app/mailboxes/mailbox_Tq3wE7rY1u',
  reason: 'Bounces 3.1% over the last 200 sends.',
})
```


```json title="Response, in send mode"
{
  "mode": "send",
  "action": {
    "$id": "https://api.sb/leaseline.app/actions/action_Sd3kQ9vT2w",
    "operation": "Mailbox.rest",
    "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
None.

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