Email marketing checklist: 10 things to check before you hit send

You can spend hours crafting the perfect email campaign - and undo it all in an instant by pressing send too soon. A broken link, a missing subject line, the wrong audience - these are the kinds of mistakes that are impossible to take back.

That's why a pre-send checklist is one of the most valuable habits an email marketer can build. It takes minutes, but it protects your reputation, your deliverability, and your relationship with your subscribers.

Here are ten things to check before every email goes out.

1. Subject line and preview text

Your subject line and preview text are the first - and sometimes only - thing your subscribers see before deciding whether to open your email. Getting them right is crucial.

For your subject line, ask yourself:

• Is it concise and to the point? Aim for under 50 characters to avoid it being cut off on mobile.
• Does it accurately reflect the email's content? Misleading subject lines damage trust and drive spam complaints.
• Is it compelling enough to earn the open?
• Have you avoided spam trigger words (things like "free!!!", excessive caps, or overly salesy language)?
• Have you personalised it where appropriate - for example, with the subscriber's first name?

For your preview text (sometimes called pre-header text):

• Does it complement the subject line rather than just repeat it?
• Is it short enough to display properly on mobile - typically 40–100 characters?
• Have you avoided leaving it blank? Empty preview text often pulls in the first line of your email, which may not make sense out of context.

For a deeper dive, our guide to writing great email subject lines covers the principles that consistently drive higher open rates.

2. Sender name and email address

Subscribers need to recognise who the email is coming from - and quickly. If your sender name looks unfamiliar, your open rate will suffer, and spam complaints will rise.

Check that:

• The sender name matches what you've used in previous campaigns. Consistency builds trust.
• The "From" email address is correct and uses your verified domain.
• You're not sending from a no-reply address if you want to encourage responses - a real, monitored inbox is always preferable.

Some subscribers will have safelisted your sending address, so changing it unexpectedly can also affect deliverability.

3. All links work correctly

Did you know that broken links in emails can do more damage than just a poor user experience? They can actively harm your sender reputation over time.

Broken or incorrect links are one of the most common and frustrating email errors - and they're entirely preventable. Click every single link in your email before it goes out.

For each link, check:

• Does it open? Is it pointing to the right destination?
• If it leads to a digital download, does the file actually download correctly?
• Do you need UTM tracking parameters for analytics? If so, are they in place?
• Are any call-to-action buttons linked, not just the text around them?

4. Proofread the content

Grammatical errors and typos make your email look careless. Even a small mistake can undermine trust and reflect poorly on your brand.

Read through the full email once for meaning, and once again specifically looking for errors. Better still, ask a colleague to proofread it - a fresh pair of eyes catches things you've become blind to.

A few practical options for proofreading:

• Use a browser extension like Grammarly to catch common mistakes.
• Paste the email copy into a clean document and read it without distractions.

Pay particular attention to personalisation fields - a "Hi {{first_name}}," that hasn't rendered correctly is one of the most common sending mistakes around.

5. Images display correctly (in both light and dark mode!)

If your email includes images, check each one carefully:

• Are they the correct images? It sounds obvious, but it's easy to accidentally leave in a placeholder.
• Do they load properly? Broken images leave unsightly gaps and look unprofessional.
• Do they have descriptive alt text? Alt text is essential for accessibility - screen readers rely on it - and also appears when images are blocked, which many email clients do by default.

An increasingly important consideration is also dark mode. Around 35% of email opens now occur in dark mode, and some email clients will automatically invert or adjust your colours.

Check that your images, logos, and buttons still look intentional - not accidental - when viewed against a dark background. Transparent PNG logos on a dark background, for example, can become invisible without specific dark mode treatment.

6. Mobile rendering

More than half of all emails are now opened on mobile devices, which means a campaign that looks great on desktop can still disappoint the majority of your audience if it hasn't been tested on smaller screens.

Before sending, check your email on at least one mobile device (or use your email platform's mobile preview). Look for:

• Text that's too small to read comfortably.
• Call-to-action buttons that are too small or too close together for a finger tap.
• Images that are too wide and require horizontal scrolling.
• Single-column layouts that break into awkward multi-column formats.

Most modern email builders - including EmailOctopus's drag-and-drop editor - produce mobile-responsive emails by default, but it's always worth verifying.

7. Test in a real inbox

Your email builder's preview mode is useful, but it's not the same as seeing your email land in a real inbox. Always send a test email to yourself - and ideally to an address on a different email client - before sending to your list.

This lets you check:

• How the email renders in your specific inbox (Gmail, Outlook, Apple Mail, etc. all handle CSS differently).
• Whether images load or are blocked by default.
• Whether the email lands in the inbox or goes to promotions/spam.
• How the subject line and preview text display in the notification and inbox view.

8. Compliance: unsubscribe link and sender details

Every marketing email you send must include a working unsubscribe link. This isn't just good practice - it's a legal requirement under GDPR, CAN-SPAM, and most other email marketing regulations worldwide.

A hard-to-find or broken unsubscribe option increases spam complaints and can result in serious penalties.

Before sending, confirm:

• There is a clearly visible unsubscribe link in the email footer.
• Your physical address or business contact details are included (required under CAN-SPAM and the UK's PECR).
• You are only sending to subscribers who have given consent to receive marketing emails.

9. You're sending to the right audience

Sending a campaign to the wrong list or segment is one of the most damaging mistakes you can make - not just for your reputation with subscribers, but potentially from a legal standpoint too.

Before you send:

• Have you selected the correct list or segment?
• If this is a targeted campaign (a promotion for a specific product, a re-engagement email for inactive subscribers, etc.), is the segmentation set up correctly?
• If you're excluding certain subscribers - for example, people who've already purchased - has that exclusion been applied?

It's worth double-checking the recipient count in your sending settings. If it looks unexpectedly high or low, investigate before proceeding.

10. DNS settings and deliverability (periodic check)

You don't need to check this for every campaign, but it's worth running periodically - particularly if you've recently changed your domain settings, moved to a new sending platform, or noticed a dip in deliverability.

Incorrect DNS settings (SPF, DKIM, and DMARC records) can cause your emails to be flagged as spam or rejected entirely - even if everything else looks perfect. A free tool like MxToolbox will check your records and flag any issues.

If you're sending through EmailOctopus with a verified domain, we perform this check automatically at the point of sending. But if you manage your own DNS or use a custom sending domain, it's a good habit to run a manual check every few months.

Your quick-reference email pre-send checklist

Here's a condensed version you can run through before every send:

• Subject line is compelling, concise, and spam-free
• Preview text complements (not duplicates) the subject line
• Sender name and email address are correct and consistent
• Every link has been clicked and tested
• UTM tracking is in place where needed
• Content has been proofread for errors
• Personalisation fields render correctly (e.g. first name tags)
• Images display correctly with alt text added
• Dark mode rendering checked
• Email tested on mobile
• Test email sent to a real inbox
• Unsubscribe link is present and working
• Sender/business details are in the footer
• Correct list or segment selected
• Recipient count looks as expected

Send with confidence

Building a pre-send checklist into your workflow is a small investment that pays off every time. The emails that land well aren't just the ones with great copy - they're the ones where everything works as intended, the moment a subscriber opens them.