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

# Inbound Sandbox

> Test inbound email processing with a dedicated Lettr sandbox inbox, no MX records needed, and inspect received messages in the dashboard.

Each team gets a dedicated sandbox inbox for testing inbound email flows without configuring MX records or setting up a production inbound domain. Emails sent to your sandbox address are stored and viewable in the dashboard.

<Note>
  This page covers the **inbound sandbox** for testing email reception. For sandbox API keys (testing email sending without real delivery), see [Sandbox API Keys](/learn/api-keys/sandbox).
</Note>

## Your Sandbox Address

Every team has a unique sandbox email address in the format:

```
{hash}@sandbox.lettr.com
```

The `{hash}` is a 12-character identifier unique to your team. Find your sandbox address on the **Sandbox** page in the dashboard.

## How It Works

<Steps>
  <Step title="Send an Email">
    Send any email to your sandbox address from any email client or service.
  </Step>

  <Step title="Lettr Receives It">
    The email is received via an inbound relay and stored automatically — the content is saved in secure storage and metadata is indexed for quick retrieval.
  </Step>

  <Step title="View in Dashboard">
    Navigate to the **Sandbox** page to see all received emails with sender, subject, and timestamp.
  </Step>

  <Step title="Inspect Details">
    Click on any email to view the full content including HTML, plain text, headers, and attachments.
  </Step>
</Steps>

## Viewing Sandbox Emails

The **Sandbox** page in the dashboard lists all emails received at your sandbox address. For each email, you can see:

* **From** — The sender's email address and name
* **Subject** — The email subject line
* **Received at** — When the email arrived
* **Content** — Full HTML and plain text content, email headers

## Retention

Sandbox emails are automatically deleted after **60 days**. This applies to both the email content and metadata. If you need to keep records longer, download or copy the content before it expires.

## Use Cases

<CardGroup cols={2}>
  <Card title="Inbound Email Development" icon="code">
    Test your inbound email parsing logic during development without configuring DNS records.
  </Card>

  <Card title="Webhook Testing" icon="webhook">
    Verify that inbound emails trigger your expected webhook events and payloads.
  </Card>

  <Card title="Reply Tracking" icon="reply">
    Test reply-to flows by sending replies to the sandbox address and inspecting the result.
  </Card>

  <Card title="CI/CD Pipelines" icon="arrows-spin">
    Use the sandbox address in automated tests to verify inbound email handling.
  </Card>
</CardGroup>

## Limitations

The inbound sandbox is designed for testing and development:

* Emails expire after 60 days
* Not suitable for production inbound email processing
* No forwarding, routing, or webhook triggering from sandbox emails

For production inbound email handling with routing rules, webhooks, and attachments, configure an [inbound domain](/learn/domains/inbound-domains) with proper MX records.

## Next Steps

<CardGroup cols={2}>
  <Card title="Inbound Domains" icon="globe" href="/learn/domains/inbound-domains">
    Set up production inbound email processing
  </Card>

  <Card title="Inbound Email" icon="inbox" href="/learn/inbound/introduction">
    Learn about inbound email handling
  </Card>
</CardGroup>