You built the email, it looks great on your screen, and you send it out. Ten minutes later someone replies: "hey, this looks broken on my end." You open it up and sure enough — an image is out of place, a section has a strange white gap, or the whole layout has collapsed into something unrecognizable.

This isn't a one-off bug. It's one of the most common — and most avoidable — problems in email marketing, and it almost always comes down to one thing: the email was never actually tested before it went out.

This guide walks through how to build your template with fewer surprises baked in, preview it properly, send yourself (and someone else) a real test copy, and know what a test still won't catch.

Why the Same Email Can Look Different in Every Inbox

Every inbox provider — Gmail, Outlook, Apple Mail, Yahoo — renders HTML and CSS a little differently, the same way two different web browsers can render a website slightly differently. Outlook in particular has a long history of being stricter than most, especially with certain layout blocks and spacing. That's why an email that looks perfect in your own inbox can still land oddly for a meaningful chunk of your list.

The practical takeaway: your own inbox is not a reliable test. It only tells you how the email renders in your client, on your device. Anything you actually want to trust needs to be checked across more than one environment before it reaches a real contact.

Build With the Right Elements From the Start

A lot of formatting issues get baked in at the design stage, before testing even enters the picture. When you're building or editing a template in Marketing > Emails > Templates, a few elements are worth extra attention:

• Text elements carry your headings and body copy, with control over font, size, color, and alignment. Templates come with default padding (top 12, bottom 12, left 24, right 24) to keep spacing consistent — worth knowing before you start manually adjusting things that were already fine.

  

• Image elements are, more often than any other block, the source of a broken layout. Pay close attention to width, height, and padding settings rather than leaving them on auto and hoping for the best.

  

• Buttons and dividers each have their own alignment and spacing controls, and small inconsistencies here are exactly the kind of thing that looks fine on a wide screen and breaks on a narrow one.

  

None of this replaces testing — but a cleanly built template gives you far fewer things to catch later.

Preview Every Version Before You Trust It

Once your template or campaign is built, open it and click Preview in the top right. From there, you can switch between Desktop, Tablet, and Mobile views to see how the layout adapts at each size. This step alone catches a surprising number of issues — a two-column layout that crowds itself on mobile, a button that's too small to tap comfortably, text that wraps in a way you didn't intend.

Preview mode shows you how the builder expects the email to render. It's a good first check, but it's still not the same as seeing the email land in an actual inbox — which is where a real test send comes in.

Send Yourself (and a Teammate) a Real Test Copy

To send an actual test:

1. Go to Marketing > Emails > Campaigns (or Templates, if you're testing a template directly) and open the one you want to check.

2. Click the three dots next to the Preview button and select Test Email.

3. Choose a Sender Email and Sender Name, enter a Receiver Email, and fill in the Preview Text and Email Subject.

4. Click Send Test Email.

   

The single most useful habit here isn't sending one test — it's sending it to more than one address, ideally across different providers (a Gmail account and an Outlook account, for example) rather than only to yourself. That's the only way to actually confirm the email behaves the way you expect outside of the builder's own preview.

What a Test Won't Catch

A few things behave differently in test sends than in a live campaign, and it's worth knowing this going in so you don't mistake normal test behavior for a bug:

• The unsubscribe link is disabled in test emails by design, to protect your list. It works normally once the campaign actually goes out.

• Test opens and clicks don't affect your analytics. Performance metrics only populate from real sends, so testing as much as you want won't skew your reporting.

• If your test didn't arrive at all, check the spam or junk folder first, confirm your sending domain and email settings are configured correctly, and try a different receiving address before assuming something is broken.

When Something Still Looks Off

If a layout issue survives all of the above, a few usual suspects are worth checking first:

• Image blocks. They're responsible for the majority of rendering issues, especially around alignment and unexpected white space.

• Mobile-specific formatting. Headings, paragraphs, and buttons each have their own mobile font size, alignment, and line-height settings, separate from the desktop version — it's easy to fix the desktop view and forget the mobile one still needs attention.

• Layout complexity. A single-column structure is consistently the safest choice for mobile readability; multi-column layouts are more prone to breaking on smaller screens.

Frequently Asked Questions

Why doesn't the unsubscribe link work in my test email? It's intentionally disabled in test sends to protect your list from accidental unsubscribes. It functions normally in a live campaign.

Do test opens and clicks affect my email analytics? No. Testing is purely for validation — your real performance data only comes from actual campaign sends.

My test email never arrived. What should I check first? Check spam/junk, confirm your sender configuration and domain settings are correct, make sure the recipient address isn't suppressed, and try sending to a different address.

Why does my email look fine on my phone but broken for a colleague on Outlook? Different email clients render HTML and CSS differently, and Outlook is historically the strictest. This is exactly why testing across more than one provider — not just your own inbox — matters.

What's usually the fastest fix when a layout looks broken? Start with the image block involved and the mobile formatting settings for that section. Between the two, they account for the large majority of formatting issues.

A broken-looking email isn't usually a design failure — it's a testing gap. Building with clean, well-configured elements, previewing across device sizes, and sending a real test to more than one inbox before you launch turns "hope it looks right" into "know it looks right."

Log in at app.ajaxunion.com, click into Marketing > Emails, open a template you're working on right now, and send yourself a real test copy before it goes out. For more guides on getting the most from your Ajax Union MarTech account, visit martechsupport.com.