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Sandbox Mode

Test your email integration without sending real emails.

Overview

Sandbox mode lets you test your email integration in development and staging environments without actually delivering emails. Emails sent with a sandbox API key are fully processed and logged in your dashboard, but never leave our servers.

Perfect for CI/CD: Run your test suite with real API calls without worrying about sending emails to actual recipients.

Creating a Sandbox API Key

  1. 1
    Go to API Keys

    Navigate to the API Keys section in your dashboard.

  2. 2
    Create new key

    Click "Create API Key" and give it a descriptive name like "Staging" or "Development".

  3. 3
    Enable sandbox mode

    Check the "Sandbox" checkbox before creating the key.

  4. 4
    Copy your key

    Copy the API key immediately—it won't be shown again.

How It Works

When you send an email using a sandbox API key:

  • The email is validated exactly like production (from address, domain verification, etc.)
  • The email is stored and visible in your dashboard
  • The delivery is marked as successful immediately
  • No email is actually sent—recipients never receive anything

Identifying Sandbox Emails

Sandbox emails are clearly marked in your dashboard with a yellow "Sandbox" badge. The delivery status will show "Sandbox (not actually sent)" so you can easily distinguish test emails from production traffic.

Use Cases

Local Development

Test email flows on your local machine without sending real emails or setting up a local mail server.

Staging Environments

Run your staging environment with the real API without accidentally emailing customers.

Automated Testing

Include email-sending code in your test suite with confidence that no emails will be delivered.

Demo Environments

Show email functionality to stakeholders without sending to real addresses.

Best Practices

  • Use environment variables to switch between sandbox and production keys based on your environment.
  • Name keys clearly like "Production", "Staging", or "CI/CD" so you know which is which.
  • Never use production keys in development or staging environments.

Works with SMTP Too

Sandbox mode works identically whether you're using the REST API or SMTP. Simply use your sandbox API key as the SMTP password, and all emails will be logged without delivery.

Environment Variables 
# Production
EML_API_KEY=your_production_key

# Staging / Development
EML_API_KEY=your_sandbox_key
Documentation