This page covers the inbound sandbox for testing email reception. For sandbox API keys (testing email sending without real delivery), see Sandbox API Keys.
Your Sandbox Address
Every team has a unique sandbox email address in the format:{hash} is a 12-character identifier unique to your team. Find your sandbox address on the Sandbox page in the dashboard.
How It Works
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.
View in Dashboard
Navigate to the Sandbox page to see all received emails with sender, subject, and timestamp.
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
Inbound Email Development
Test your inbound email parsing logic during development without configuring DNS records.
Webhook Testing
Verify that inbound emails trigger your expected webhook events and payloads.
Reply Tracking
Test reply-to flows by sending replies to the sandbox address and inspecting the result.
CI/CD Pipelines
Use the sandbox address in automated tests to verify inbound email handling.
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
Next Steps
Inbound Domains
Set up production inbound email processing
Receiving Email
Learn about inbound email handling