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Modular Mail Docs

Sending Test Emails

Send a test email to preview exactly how your campaign will look in a real inbox before you export and send it to your list.

When to use Send Test

Section titled “When to use Send Test”

Test emails are useful at several points in your workflow:

  • Before review — send to yourself or a colleague to check layout and content in a real email client
  • Cross-client checking — send to accounts on Gmail, Outlook, and Apple Mail to compare rendering
  • Proofreading — a final check before exporting to your ESP

The test email uses your campaign’s current saved state, including all content edits, style selections, and module choices.

How to send a test

Section titled “How to send a test”
  1. Open your campaign in the editor
  2. Click Send Test in the editor toolbar
  3. Enter one or more recipient email addresses in the Recipients field
  4. Review or edit the Subject line
  5. Optionally, check Add timestamp to subject line to make each send easy to identify in your inbox
  6. Click Send Test

The modal stays open after sending so you can review the result and send to additional recipients without reopening it.

Tip: Click any address in the Recent chips row to add a previously used recipient address without re-typing it.

Recipients

Section titled “Recipients”

Enter recipient addresses in the text area, separated by commas, spaces, or new lines. You can send to up to 10 recipients per send.

[email protected], [email protected]
[email protected]

Subject line and timestamp

Section titled “Subject line and timestamp”

The subject line pre-fills with your campaign name. You can edit it for the test send without affecting the campaign name.

Checking Add timestamp to subject line appends the current local date and time in YYYY-MM-DD HH:MM:SS format. This is useful when sending multiple rapid tests — each arrives with a distinct subject line so you can easily match inbox messages to specific iterations.

The subject in your inbox will appear as:

[MM-TEST] Spring Sale Announcement (2026-05-07 14:32:11)

The [MM-TEST] prefix is always added automatically. It cannot be removed — it exists to prevent accidental sends to production lists.

Daily quota

Section titled “Daily quota”

Each workspace has a daily limit on test email sends. The modal shows how many tests you have used today and your daily limit.

If you reach the limit, you will need to wait until the quota resets at midnight UTC.

Note: The quota counts accepted recipients, not sends. Sending one test to three recipients uses three of your daily quota.

Troubleshooting

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Test arrived but images are broken. Image URLs in your campaign must be publicly accessible. Local or development image paths will not load in a real inbox.

Test did not arrive. Check your spam folder. The [MM-TEST] prefix and sending domain may trigger spam filters, especially with new email addresses. Add the sending address to your contacts if needed.

“Please wait N seconds” message. There is a short cooldown between sends. Wait a few seconds and try again.

“Daily limit reached” message. Your workspace has used its daily test email quota. The limit resets at midnight UTC.

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