> ## Documentation Index
> Fetch the complete documentation index at: https://docs.thepostalcompany.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Send physical letters programmatically with The Postal Company API.

# The Postal Company API

The Postal Company API lets you send physical letters anywhere in the world from your application. Write your letter content, provide a recipient address, and we handle printing, enveloping, and postal delivery.

## Quick start

<Steps>
  <Step title="Create an account">
    Sign up at [thepostalcompany.com](https://thepostalcompany.com) and log in to your dashboard.
  </Step>

  <Step title="Top up your balance">
    Go to the [Balance](https://thepostalcompany.com/balance) page and purchase credits. Each letter costs €2.50.
  </Step>

  <Step title="Create an API key">
    Go to [API Keys](https://thepostalcompany.com/api-keys) and create a new key. Copy it — it's only shown once.
  </Step>

  <Step title="Send a letter">
    ```bash theme={null}
    curl -X POST https://thepostalcompany.com/api/v1/letters \
      -H "Authorization: Bearer tpc_your_api_key" \
      -H "Content-Type: application/json" \
      -d '{
        "recipient": "Jane Doe",
        "address": {
          "street": "Keizersgracht",
          "number": "123",
          "postalcode": "1015 CJ",
          "city": "Amsterdam",
          "country": "NL"
        },
        "content": "Dear Jane,\n\nThis is a test letter sent via the API.\n\nBest regards"
      }'
    ```
  </Step>
</Steps>

## Key concepts

* **Credits** — Pre-paid balance used to send letters. Each letter costs €2.50 via checkout or €2.25 via API.
* **API keys** — Long-lived keys for authenticating API requests. You can create multiple keys and revoke them at any time.
* **Letters** — Create letters as drafts to review them first, or send immediately. Once sent, letters are queued for printing and postal delivery.
* **Drafts** — Letters created with `send: false` are saved as drafts. You can update them with `PATCH` and send them when ready with `POST /api/v1/letters/:id/send`.

## AI agent skill

If you're using an AI coding agent (like Claude Code, Cursor, or Copilot), you can download our [agent skill file](https://thepostalcompany.com/skill.md) to give your agent full knowledge of the API. Add it to your project or paste it into your agent's context.