---
title: "Sandbox: Create an Inbound Mail Item"
method: POST
path: "/simulations/inbound_mail_items"
---

# Sandbox: Create an Inbound Mail Item

`POST /simulations/inbound_mail_items`

Simulates an Inbound Mail Item to one of your Lockbox Addresses or Lockbox Recipients, as if someone had mailed a physical check. Increase automatically deposits a check mailed to a Lockbox Recipient into the recipient's Account. A check mailed to a Lockbox Address must be deposited or ignored with the [Action an Inbound Mail Item](#inbound-mail-items) endpoint.

## Request body

- SandboxCreateAnInboundMailItemParameters
  - `amount` integer, required — The amount of the check to be simulated, in cents.
  - `contents_file_id` string — The file containing the PDF contents. If not present, a default check image file will be used.
  - `lockbox_address_id` string — The identifier of the Lockbox Address to simulate inbound mail to. Exactly one lockbox identifier parameter must be provided.
  - `lockbox_recipient_id` string — The identifier of the Lockbox Recipient to simulate inbound mail to. Exactly one lockbox identifier parameter must be provided.

## Response `200`

Inbound Mail Item

- InboundMailItem — Inbound Mail Items represent pieces of physical mail delivered to a Lockbox Address. Increase automatically deposits checks mailed to a Lockbox Recipient into the recipient's Account. Checks that are not matched to a Lockbox Recipient must be deposited or ignored using the Action an Inbound Mail Item endpoint.
  - `checks` InboundMailItemCheck[], required — The checks in the mail item.
    - `amount` integer, required — The amount of the check.
    - `back_file_id` string, nullable, required — The identifier for the File containing the back of the check.
    - `check_deposit_id` string, nullable, required — The identifier of the Check Deposit if this check was deposited.
    - `front_file_id` string, nullable, required — The identifier for the File containing the front of the check.
    - `status` 'pending' | 'deposited' | 'ignored', nullable, required — The status of the Inbound Mail Item Check.
  - `created_at` string, date-time, required — The [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) time at which the Inbound Mail Item was created.
  - `file_id` string, required — The identifier for the File containing the scanned contents of the mail item.
  - `id` string, required — The Inbound Mail Item identifier.
  - `lockbox_address_id` string, required — The identifier for the Lockbox Address that received this mail item.
  - `lockbox_recipient_id` string, nullable, required — The identifier for the Lockbox Recipient that received this mail item. For mail items that could not be routed to a Lockbox Recipient, this will be null.
  - `recipient_name` string, nullable, required — The recipient name as written on the mail item.
  - `rejection_reason` 'no_matching_lockbox' | 'no_check' | 'lockbox_not_active' | 'lockbox_address_not_active' | 'lockbox_recipient_not_active', nullable, required — If the mail item has been rejected, why it was rejected.
  - `status` 'pending' | 'processed' | 'rejected', required — If the mail item has been processed.
  - `type` 'inbound_mail_item', required — A constant representing the object's type. For this resource it will always be `inbound_mail_item`.

## Other responses

- `4XX` — Error
- `5XX` — Error

---

[API](https://skmtc.net/increase/apis/increase-api-2.md) · [All operations](https://skmtc.net/increase/apis/increase-api-2/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/increase/increase-api-2/versions/e968bcd4dcf9/schema)