This page covers the inbound sandbox for inspecting received email. 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, where you can copy it with one click. No DNS setup is needed.
How It Works
1
Send an Email
Send any email to your sandbox address from any email client or service.
2
Lettr Receives It
The email is received and stored in your team’s sandbox.
3
View in Dashboard
Navigate to the Sandbox page to see all received emails with sender, subject, and the time they arrived.
4
Inspect Details
Click an email to open it. The detail view has three tabs: HTML Preview, Plain Text, and Headers.
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
- Subject: The email subject line
- Received: When the email arrived
Retention
Emails are stored for 60 days. If you need to keep a message longer, copy its content before then.Use Cases
Check What Arrives
See how an email renders and what headers it carries when it is received, without setting up DNS.
Reply Flows by Hand
Use the sandbox address as a reply-to, reply to the email yourself, and inspect what the reply looks like.
Limitations
The inbound sandbox is for inspecting email by hand, not for testing your endpoint:- Sandbox emails are never forwarded. They don’t reach your forwarding URL and don’t trigger your webhooks.
- Attachments are not stored or shown
- Emails are stored for 60 days
- Not suitable for production inbound email processing
inbound-test.example.com) and send mail to it.
Next Steps
Inbound Domains
Set up production inbound email processing
Inbound Email
Learn about inbound email handling