Mobile Checkout Optimization for Shopify

Here's a number that should concern you: mobile is 60%+ of e-commerce traffic but converts at roughly half the rate of desktop.

That gap isn't because mobile shoppers don't want to buy. It's because most mobile checkouts are desktop checkouts crammed onto a small screen. They weren't designed for thumbs, for distractions, for typing on glass.

I've done a lot of mobile checkout audits. The problems are almost always the same, and they're almost always fixable.

Why Mobile Checkout Is Different

Desktop checkout: someone sitting at a desk, focused, with a full keyboard and big screen.

Mobile checkout: someone on a bus, holding a phone with one hand, getting notifications, with a tiny keyboard and a screen that shows maybe two form fields at a time.

Same checkout form, completely different experience.

The typing alone is brutal. Entering a 16-digit credit card number on a phone keyboard has about a 15% error rate. Full addresses with autocorrect fighting you. Switching between letter and number keyboards.

Express payment options (Apple Pay, Shop Pay) bypass all of this. On mobile, they're not a nice-to-have, they're essential.

The Mobile Checkout Audit

Go through your checkout on your phone right now. Not in Chrome DevTools simulating mobile, on an actual phone. Try to buy something.

Things to check:

1. First Impression

• How long did it take to load?
• Can you see the most important elements without scrolling?
• Are express payment options (Shop Pay, Apple Pay) immediately visible?
• Does it feel cramped or spacious?

2. Form Fields

• Are fields large enough to tap easily?
• Does tapping a field show the right keyboard? (numbers for card, email keyboard for email)
• Is autocomplete working?
• Can you see what you're typing? (field doesn't get hidden by keyboard)

3. Navigation

• Is there horizontal scrolling anywhere? (This should never happen)
• Can you easily move between fields?
• Is the "Next" button visible when keyboard is open?
• Can you go back easily if you make a mistake?

4. Payment

• How prominent are express payment options?
• Is entering credit card info painful?
• Are error messages clear and specific?
• Does the total stay visible?

Most stores fail at least half of these. That's why mobile converts poorly.

The Fixes (In Order of Impact)

1. Make Express Checkout Impossible to Miss

On mobile, Shop Pay and Apple Pay should be the first things people see. Not tucked below the fold. Not in a secondary tab. Primary position.

If someone uses Apple Pay, they're done in 3 seconds. No typing, no forms, no friction. That's what you want.

What this looks like:

• Express payment buttons at top of checkout
• "Or pay with card" below (as secondary option)
• Buttons large enough to tap easily (minimum 44px height)

A beauty brand moved their Apple Pay button from below the form to above it. Mobile checkout conversion increased 23%. Same button, different position.

2. Fix Your Form Fields

Mobile form fields need to be:

• At least 44px tall (Apple's minimum tap target)
• Full width or nearly full width
• Clearly labeled (labels above fields, not inside)
• Spaced apart (so thumbs don't hit the wrong one)

Keyboard types matter:

• Email fields should trigger email keyboard (with @ symbol)
• Phone fields should trigger number pad
• Credit card should trigger number pad
• ZIP code should trigger number pad

On Shopify, this should happen automatically if you're using standard checkout. If not, check your theme customizations.

3. Enable Address Autocomplete

Address autocomplete (powered by Google Places API) transforms mobile checkout:

• User types "123 Ma..."
• Suggestions appear
• One tap fills entire address

This eliminates 80% of address typing. On mobile, that's huge.

Shopify has this built in, but make sure it's working. Some themes or customizations break it.

4. Eliminate Horizontal Scrolling

If any part of your checkout requires horizontal scrolling on mobile, fix it immediately. This usually means:

• Tables that are too wide
• Images that aren't responsive
• Fixed-width elements
• Unresponsive forms

Test at 375px width (iPhone SE size). Everything should fit.

5. Sticky Call-to-Action

On desktop, the checkout button is always visible. On mobile, you might scroll past it.

Consider a sticky checkout button that stays fixed at the bottom of the screen. Always visible, always accessible.

Some themes do this automatically. If yours doesn't, it's worth adding.

6. Collapse Non-Essential Info

Order summary on mobile should be collapsible:

• Show total prominently
• "View order details" expands to show items
• Saves vertical space
• Reduces cognitive load

Same with shipping options, if there's only one option, don't make it a selection step.

The Mobile Payment Stack

Express payments are non-negotiable on mobile:

Shop Pay Shopify's express checkout. Works across all Shopify stores. Stores payment and shipping info. Should be your primary checkout option on mobile.

Apple Pay One-touch payment for iOS users. No typing, no forms. Face ID or Touch ID confirmation. About 45% of US smartphones are iPhones.

Google Pay Same benefits for Android users. One-touch, stored credentials.

PayPal Still converts well, especially for older demographics. One-tap if they're logged into PayPal app.

Order of priority: Shop Pay > Apple Pay/Google Pay > PayPal > Credit card

Why This Order?

Shop Pay is optimized for Shopify. It handles shipping, payment, everything. Fastest possible checkout.

Apple Pay and Google Pay are next-best, one-touch payment but may still need shipping info.

PayPal is good but opens another app/tab, which can break mobile flow.

Credit card entry should be last resort on mobile. It's where friction lives.

Common Mobile Checkout Mistakes

1. Asking for Unnecessary Info

Every field is harder on mobile. That "How did you hear about us?" field that's mildly annoying on desktop is a real obstacle on mobile.

Audit every field:

• Is this legally required?
• Does it directly help fulfill the order?
• Can we get this info another way?

If no to all three, remove it.

2. Tiny Touch Targets

Buttons and links designed for mouse precision don't work for thumbs. The "Change" link that's 12px text? Good luck tapping that accurately.

Minimum touch targets: 44x44 pixels. Ideally 48x48.

3. Poor Error Handling

"Invalid input" is useless. On mobile, be specific:

• "Card number should be 16 digits"
• "Please enter a valid email address"
• "This ZIP code doesn't match the selected state"

And show errors inline, next to the relevant field. Don't make people hunt for what went wrong.

4. Hiding the Keyboard

Make sure tapping a form field doesn't cause the keyboard to cover that field. The page should scroll so the active field is visible.

This is especially common with the payment section, card fields at bottom of form get covered by keyboard.

5. No Visual Feedback

When something's loading on mobile, show it. Unclear loading states make people tap again, causing double-submissions or errors.

Loading spinners, progress bars, button state changes, all important on mobile.

Testing Mobile Checkout

Real Device Testing

Chrome DevTools mobile simulation is useful for layout, but it doesn't capture:

• Actual touch targets (your thumb vs mouse)
• Real keyboard behavior
• Device-specific quirks
• True network conditions

Test on actual phones. iPhone and Android. New and old models.

The Stranger Test

Have someone unfamiliar with your brand try to check out on mobile. Watch them. Don't help.

Where do they hesitate? What do they tap accidentally? Where do they look confused?

This will tell you more than any analytics tool.

Speed Testing

Test on throttled connections. On 3G, not WiFi.

Mobile shoppers often have inconsistent network. What happens on a slow connection matters.

Case Study: Mobile Conversion Doubled

An accessories brand had:

• Desktop conversion: 3.2%
• Mobile conversion: 1.4%

Gap was clearly a mobile problem. Audit found:

• Express payment buried below fold
• Form fields were 32px tall (too small)
• No address autocomplete
• Order summary taking up half the screen
• "Continue" button hidden when keyboard open

Changes made:

• Shop Pay and Apple Pay moved to top
• Form fields enlarged to 48px
• Address autocomplete enabled
• Collapsible order summary
• Sticky bottom CTA

Results after 30 days:

• Mobile conversion: 2.6%
• Nearly doubled, still room to grow
• Gap with desktop narrowed significantly

The Mobile Checklist

Before launching any checkout changes, verify:

Layout

• [ ] No horizontal scrolling
• [ ] Single-column forms
• [ ] Collapsible order summary
• [ ] Sticky CTA button

Touch Targets

• [ ] All buttons 44px+ height
• [ ] Links large enough to tap
• [ ] Spacing between tap targets
• [ ] Form fields easy to select

Payments

• [ ] Express payments above fold
• [ ] Apple Pay/Google Pay enabled
• [ ] Shop Pay enabled
• [ ] Credit card as last option

Forms

• [ ] Correct keyboard types
• [ ] Address autocomplete working
• [ ] Labels above (not inside) fields
• [ ] Inline error messages

Performance

• [ ] Loads in under 3 seconds on 3G
• [ ] No render-blocking scripts
• [ ] Images optimized for mobile
• [ ] Loading states clear

The Bottom Line

Mobile checkout is where most stores are losing money. The good news: the fixes are mostly straightforward.

1. Make express payment primary
2. Fix form fields for thumbs
3. Enable autocomplete
4. Remove unnecessary friction
5. Test on real phones

Your mobile conversion rate should be within 30% of desktop. If the gap is bigger, there's work to do.

Start with express payments. It's the single highest-impact change you can make for mobile checkout.