Mamba speeds up WooCommerce checkout by deferring non-critical assets, reducing redundant AJAX calls, and preparing payment SDKs efficiently—without breaking functionality. These options are available in the Performance → Overhead tab and can be enabled individually to tune checkout performance for your store.

The goals:

• Faster first paint and interaction on the checkout page
• Fewer unnecessary AJAX calls and script execution
• Smoother payment script loading and network setup
• Preserved correctness for carts, payments, emails, and UI

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Optimize Checkout JavaScript

What it does:

• Defers non-critical WooCommerce checkout scripts (e.g., country select, address i18n, payment method helpers)
• Lets the page render and become interactive faster

When it applies:

• Checkout page only
• Active only when enabled

Why it’s safe:

• Core, critical scripts still run
• Helpers are simply deferred until after initial paint

Tip: Use alongside Lazy Load Payment Methods for maximum effect.

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Optimize Checkout CSS

What it does:

• Dequeues non-critical WooCommerce styles (layout and smallscreen) on checkout
• Trims CSS payload and reduces render work

When it applies:

• Checkout page only
• Active only when enabled

Why it’s safe:

• Core checkout styles remain intact
• Only non-critical layers are removed

Tip: If your theme depends on these layers, adjust with child-theme CSS or leave this option off.

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Smart Cart Fragments (Checkout)

What it does:

• Prevents WooCommerce’s cart fragments script from running at checkout if no cart widget is present
• Cuts redundant AJAX calls and script execution

When it applies:

• Checkout page only
• Enabled only if a cart widget/block/template isn’t detected

Why it’s safe:

• If a cart widget is present, the optimization does not run
• Behavior remains correct for all themes

Tip: Most modern themes don’t show a mini-cart at checkout, so this is usually safe to enable.

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Lazy Load Payment Methods

What it does:

• Defers payment gateway scripts (Stripe, PayPal, Square, Klarna, WooCommerce Payments, etc.)
• Allows the page to render without blocking

When it applies:

• Checkout page only
• Active only when enabled

Why it’s safe:

• Gateways still initialize correctly
• They load after the page becomes interactive

Tip: Pair with Preconnect Payment SDKs to minimize visible delays.

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Defer Transactional Emails

What it does:

• Defers WooCommerce transactional email dispatch during checkout
• Prevents email sending from slowing down the “place order” step

When it applies:

• Checkout page only
• Active only when enabled

Why it’s safe:

• Emails still send, but at WooCommerce’s deferred timing
• Order flows and notifications remain correct

Tip: Especially helpful on stores with heavier SMTP/email stacks.

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Preconnect Payment SDKs

What it does:

• Adds <link rel="preconnect"> for major payment domains (Stripe, PayPal, Google Pay, Square, Klarna, Apple Pay, Authorize.net, Braintree, Adyen, etc.)
• Primes network connections before gateway scripts load

When it applies:

• Checkout page only
• Active only when enabled

Why it’s safe:

• Preconnect is a harmless hint—minimal overhead if unused
• Noticeable startup improvement if the gateway is used

Tip: Keep enabled on most stores, especially those offering multiple payment methods.

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Troubleshooting

• Styling looks off after enabling “Optimize Checkout CSS”
  → Your theme may depend on WooCommerce’s layout/smallscreen CSS. Leave this off or add minimal overrides in your child theme.
• Payment UI appears with a short delay
  → Expected when using Lazy Load Payment Methods. Pair with Preconnect Payment SDKs to minimize the gap.
• Cart totals/mini-cart not updating on checkout
  → If your checkout includes a mini-cart, disable Smart Cart Fragments (Checkout) so WooCommerce’s script runs as normal.
• “Place order” step feels slow
  → Enable Defer Transactional Emails. If still slow, investigate gateway/API latency or SMTP performance.

Mamba’s checkout optimizations are safe by default and reversible per toggle. Enable them incrementally, validate with your theme and gateways, and keep the ones that deliver the best improvements to speed-to-conversion for your store.