Why a Test Send Isn't Enough: See Your Newsletter in Real Gmail and Outlook Inboxes
Every newsletter team has a version of the same ritual. Send a test to yourself, scroll through it, maybe forward it to a coworker and ask who has Outlook.
It’s better than nothing. But it shows you one inbox, on one screen, the way your own account treats your own email.
What a test send misses
- Other inboxes. Gmail and Outlook display the same HTML differently. If you only check one, you only know about one.
- Other screen sizes. A layout that looks fine on a desktop can stack badly in a narrow window.
- Gmail’s clip. Gmail cuts off emails with more than about 102KB of HTML. You might not notice in your own copy if you know what’s below the cut.
- Your readers’ view. Your own account may know you, trust you and show your images by default. A reader’s may not.
What to check before every send
- Links. Every link goes somewhere, and to the right place.
- Weight. The HTML is well under Gmail’s ~102KB limit.
- Layout. Columns, buttons and images hold up on a desktop screen and in a narrow window.
- Images. They load, they’re the right size, and they have descriptions for readers who don’t load images.
- Inboxes. It looks right in the inboxes most of your readers use, at least Gmail and Outlook.
Run steps 1 and 2 through Preflight’s email check first. It’s instant and doesn’t use up anything.
See it in real inboxes
For steps 3 to 5, you want screenshots from real inboxes, not a simulation.
Inbox preview sends your HTML to our own Gmail and Outlook.com test inboxes, opens it there and takes screenshots on a desktop screen and at phone width. A few minutes later you get the screenshots, plus whether Gmail clipped it.
What it doesn’t cover
Inbox preview shows Gmail and Outlook.com on the web. It doesn’t show the Gmail or Outlook phone apps, Outlook for Windows or Mac, or Apple Mail. Phone width means the web inbox in a narrow window.
If you need to see dozens of email clients and devices for every send, that’s what paid testing suites are for. We wrote up Inbox preview vs. Litmus to help you decide.
In Letterhead
Letterhead’s composer checks every issue before you send: links that won’t work, bounce risk, readability and Email Weight, with what’s making it heavy.
Frequently asked questions
How do I preview an email in Outlook before sending? Paste your HTML into the Outlook email preview, which photographs it in a real Outlook.com inbox. You can also send a test to an Outlook.com address you own.
Is Inbox preview free? Yes. One preview a day, no signup.
What happens to the email I paste? It’s sent to our test inboxes and stays there. The screenshots are deleted after a week, so don’t paste anything confidential.