---
title: "Extend an active inbox by seven days with Stripe MPP for $1.00"
method: POST
path: "/api/v1/inboxes/{inboxId}/extend"
tags: ["Inboxes"]
---

# Extend an active inbox by seven days with Stripe MPP for $1.00

`POST /api/v1/inboxes/{inboxId}/extend`

## Request

- Base URL: `https://machineinbox.com`
- URL: `https://machineinbox.com/api/v1/inboxes/{inboxId}/extend`
- Auth: none required

Adds seven days to the current expiry. The mailbox token goes in the X-Mailbox-Token header because Authorization carries the MPP Payment credential on the paid retry. An inbox can never live more than 35 days into the future, and an expired inbox cannot be extended - extend at least ten minutes before expiry.

## Path parameters

- `inboxId` string, uuid, required

## Headers

- `X-Mailbox-Token` string
- `Idempotency-Key` string

## Request body

- object

## Response `200`

Extension applied; the new expiry is returned.

- ExtendInboxResponse
  - `extension` object, required
    - `inboxId` string, uuid, required
    - `days` integer, required
    - `expiresAt` string, date-time, required
  - `applied` unknown, required
  - `replayed` boolean, required

## Other responses

- `401`: A valid mailbox bearer token is required.
- `402`: Payment is required. The one 402 advertises both rails: Stripe MPP in WWW-Authenticate and x402 v2 in PAYMENT-REQUIRED. Pay with either.
- `403`: The inbox is suspended.
- `404`: The inbox, message, attachment, or route was not found.
- `409`: The idempotency key was already used for another operation.
- `410`: The inbox has expired.
- `429`: A request or reply limit was reached.

---

[API](https://skmtc.dev/machineinbox/apis/machine-inbox-api.md) · [All operations](https://skmtc.dev/machineinbox/apis/machine-inbox-api/llms.txt) · [OpenAPI document](https://skmtc.dev/machineinbox/apis/machine-inbox-api/revisions/bcb3cf08ad6d?raw)