---
name: letters-routes
description: Handle 4 OpenAPI operation(s) under /letters for the letters route group.
---

# letters API Routes

Handle 4 OpenAPI operation(s) under /letters for the letters route group.

Use the generated operation tools to make real API calls. Do not invent API responses.
If a tool reports missing setup, return the exact setup field name to the caller.
For write, update, or delete operations, state the intended action before calling the tool.

## Operations

### letter_retrieve

- Operation ID: `letter_retrieve`
- Route: `GET /letters/{ltr_id}`
- Mode: READ
- Summary: Retrieve
- Parameters:
  - `ltr_id` in `path` required

### letter_cancel

- Operation ID: `letter_cancel`
- Route: `DELETE /letters/{ltr_id}`
- Mode: WRITE
- Summary: Cancel
- Parameters:
  - `ltr_id` in `path` required

### letters_list

- Operation ID: `letters_list`
- Route: `GET /letters`
- Mode: READ
- Summary: List
- Parameters:
  - `limit` in `query`
  - `before/after` in `query`
  - `include` in `query`
  - `date_created` in `query`
  - `metadata` in `query`
  - `campaign_id` in `query`
  - `status` in `query`
  - `color` in `query`
  - `scheduled` in `query`
  - `send_date` in `query`
  - `mail_type` in `query`
  - `sort_by` in `query`

### letter_create

- Operation ID: `letter_create`
- Route: `POST /letters`
- Mode: WRITE
- Summary: Create
- Parameters:
  - `Idempotency-Key` in `header`
  - `idempotency_key` in `query`
  - `Lob-Version` in `header`
- Body: JSON request body accepted.