Mobile-first email: templates, subject lines and send times

Before you change anything, pull the device and client report from your email service provider. MailChimp, Constant Contact, Campaign Monitor, Emma and ExactTarget all report opens by client. You want three figures.

• Share of opens on mobile. Typically 45 to 60 percent for US lists this year.
• Share of clicks on mobile. Usually lower than opens, which tells you how much the current design is costing you.
• Top three clients. For most lists that is iPhone Mail, Gmail and iPad, in some order. Outlook still matters for B2B.

The gap between mobile opens and mobile clicks is your opportunity. If 55 percent of people open on a phone but only 30 percent of clicks come from one, the email is being read and abandoned.

You do not need a complex responsive build to get most of the benefit. These rules cover the majority of cases.

1. One column, 600 pixels wide maximum. Multi-column layouts shrink to unreadable size on a phone unless you use media queries to stack them, and Gmail's mobile apps ignore media queries entirely.
2. Body text at 16 pixels or larger, headlines at 22 or more. Apple's iOS Mail will auto-scale smaller text in unpredictable ways. Set the size you want.
3. Buttons at least 44 by 44 pixels, built in HTML and CSS rather than as images. Images are off by default in many clients and a button that does not render is a lost click.
4. Space between tappable links. Stacked text links a few pixels apart are a fat-finger trap. Give each one its own line with padding.
5. Images with alt text and a defined width. Set width in both the HTML attribute and inline CSS. Keep total email weight under 100 KB where you can; a slow load over a cellular connection is a closed email.
6. Inline your CSS. Gmail strips the head section. Use an inliner tool before sending.
7. One clear call to action in the first screen. On a phone the first screen is roughly 320 by 480 pixels after the client's own header. Whatever you most want people to do must be visible there.

If you do go responsive, test the media-query version and the fallback version separately. Litmus and Email on Acid both render across the major clients for a monthly fee, and that fee is small compared with a broken campaign to a six-figure list.

The subject line is cut off at different lengths depending on the client, and on phones it is short.

Practical rules:

• Front-load the point. The first 30 characters have to carry the message. "Spring sale: 25% off outerwear this weekend" survives truncation. "This weekend only, our biggest spring savings on 25% off outerwear" does not.
• Write the preheader on purpose. It is the first line of text in the email body, shown after the subject in most mobile clients. If you leave it blank the client shows "View this email in your browser." Use it to extend the subject, 40 to 90 characters.
• Personalization helps, but less than relevance. First names in subject lines give a small lift in most tests. Sending the right offer to the right segment gives a larger one.
• Avoid all-caps and multiple exclamation points. They look like spam on a small screen and they feed spam filters.
• Test two subject lines on every campaign. Most providers will send each variant to 10 to 20 percent of the list and the winner to the rest. There is no reason not to.

The old advice, Tuesday and Thursday at 10 a.m., came from an era when email was read at a desk. Phones changed the shape of the day. Opens now cluster early morning (6 to 8 a.m.), lunchtime, and evening (8 to 10 p.m.), and weekends are no longer dead for consumer lists.

Rather than adopting someone else's chart, run a simple test.

1. Pick one regular campaign and split the list three ways randomly.
2. Send at three times, for example 7 a.m., 12 p.m. and 8 p.m. local, for four consecutive sends.
3. Compare click rate and, if you can track it, conversion rate. Ignore opens as the deciding metric; they move with the phone-checking habit and not with intent.
4. Then test the day of the week with the same method.

Send-time optimization features, which deliver to each subscriber at the hour they usually open, are available from a few providers now and are worth trying if you have the volume, but a well-run manual test gets most of the way there.

Half of the mobile failures we see are not in the email at all. The subscriber taps a big friendly button and lands on a desktop page with a three-column layout and a form that needs pinch-zooming. Check every link in a campaign on a phone before you send. If the destination page is not responsive, send mobile traffic to a simpler page built for the purpose. Google's mobile-friendly ranking change arrives on April 21, so this work pays twice.

CAN-SPAM has not changed: a working unsubscribe that is honored within ten business days, a physical mailing address in every message, and a subject line that is not deceptive. Make the unsubscribe link large enough to tap. A frustrated subscriber who cannot find it will hit the spam button instead, and that hurts deliverability for the whole list.

• Designing the desktop version first and "checking" mobile at the end.
• Image-only emails. When images are blocked the subscriber sees a blank screen.
• Tiny text links in the footer carrying the main call to action.
• Sending from a no-reply address. Replies on a phone are a natural behavior; let them happen and route them.
• Measuring success by open rate alone, when Apple's and Gmail's image handling make opens less reliable every year.

Email sits inside a connected program across brand, growth, web and technology rather than as a standalone tool. Discover means reading the device and client reports, reviewing the last six months of campaigns on real phones, and checking where the links land. Plan sets the template system, the segmentation that decides who gets what, the testing calendar for subject lines and send times, and the landing pages the web team needs to build. Build is the responsive template, tested across clients, plus the automation flows (welcome, abandoned cart, post-purchase) that do most of the revenue work on a retail list. Improve is the monthly review: what won the tests, what the mobile click share did, and what to change next.

The ecommerce growth engagement is the representative pattern for this work. A retailer with a healthy list was seeing mobile opens above half while mobile revenue from email lagged well behind. The template was rebuilt as a single-column, button-led design, the product pages linked from campaigns were made responsive at the same time, and abandoned-cart and welcome flows were added with the same mobile rules. Email revenue per send rose, and the mobile share of email-driven orders climbed to match the share of opens within a season.