Preview & Test¶
Always preview your campaign before sending. MailJawn gives you two ways to check your work: a live HTML preview and test emails to your own inbox.
Live Preview¶
As you write your MJML, MailJawn compiles it to HTML and renders a live preview. This shows you exactly how the email will look — layout, fonts, colors, and images — without needing to send anything.
The preview renders your template variables with sample data so you can see how personalization will look:
| Variable | Preview Value |
|---|---|
{{ subscriber.name }} |
Preview Recipient |
{{ subscriber.email }} |
(your account email) |
{{ company_name }} |
(your organization name) |
{{ address }} |
(your organization address) |
{{ unsubscribe_url }} |
(a non-tracking preview link) |
Note
The preview unsubscribe link points to a preview route, not a real tracking URL. It won't actually unsubscribe anyone.
Test Emails¶
A test email sends the fully compiled campaign to your inbox so you can check it in a real email client. This catches things the preview might miss — like how your email renders in Gmail vs. Apple Mail, or whether your links actually work.
What's Different About Test Emails¶
- The subject line is prefixed with [Preview] so you can easily spot test messages
- Template variables are rendered with the same sample data as the live preview
- No tracking is applied — open tracking pixels, click tracking, and unsubscribe tracking are all disabled
- The email is sent to your organization's owner email address
When to Send a Test¶
Send a test email when you want to:
- Check rendering in your actual email client (Gmail, Apple Mail, Outlook, etc.)
- Verify links work correctly by clicking them
- Review on mobile by opening the test email on your phone
- Proofread in a more realistic context than the editor
Tip
Send yourself a test email, open it on your phone, and read it as if you were a subscriber. Does the most important content appear above the fold? Is the call-to-action button easy to tap?
Preview Compilation¶
You can preview your MJML at any time, even before saving the campaign. MailJawn compiles the MJML to HTML on the fly and returns the rendered result. This is useful for rapid iteration while you're still drafting.
Checklist Before Sending¶
Before moving from preview to send, verify:
- [ ] Subject line is clear and free of typos
- [ ] Template variables render correctly (no blank spots where names should be)
- [ ] All links point to the right destinations
- [ ] Images load and have alt text
- [ ] The email looks good on mobile (single-column, readable text size)
- [ ] Footer includes unsubscribe link and mailing address
- [ ] Targeting is set to the right audience