Shopify Scripts: Custom Checkout Logic Without the App Bloat

Your Shopify Plus store doesn't need another app. Every time you install one to handle custom checkout logic, wholesale pricing, or conditional shipping rates, you're adding weight to your tech stack, slowing down your site, and creating potential conflict points between integrations.

Here's what you need to know: Shopify Scripts give you native, server-side control over checkout behavior without touching the app ecosystem. They run directly on Shopify's infrastructure, executing custom logic at the exact moment customers interact with their cart and checkout.

For brands serious about speed and control, Scripts eliminate the middleman entirely.

What Shopify Scripts Actually Are

Shopify Scripts are custom code blocks that modify cart and checkout behavior in real-time. They're written in Ruby and execute on Shopify's backend servers, meaning zero impact on frontend performance.

Unlike apps that inject JavaScript, add external API calls, or load third-party resources, Scripts operate natively within Shopify's checkout flow. The logic runs server-side before customers see their final pricing, shipping options, or payment methods.

Key advantage: You're not relying on external services to process requests. Everything happens within Shopify's infrastructure, which means faster execution and no additional points of failure.

Scripts are exclusive to Shopify Plus stores, and they come in three distinct categories, each targeting a specific part of the checkout experience.

The Three Types of Shopify Scripts

Line Item Scripts

These modify what's in the cart itself. You can apply dynamic discounts, adjust pricing based on customer attributes, or add/remove items based on conditions you define.

Practical applications:

• Automatic volume discounts that adjust as customers add more units
• Customer-specific pricing for wholesale accounts tagged in your system
• BOGO promotions that trigger based on cart contents
• Conditional product bundles with custom pricing logic

Line Item Scripts read cart data, customer tags, product properties, and metafields to determine what logic to apply. They execute before the customer proceeds to payment, ensuring displayed prices reflect your actual business rules.

Shipping Scripts

Control which shipping options appear, modify rates based on cart conditions, or hide certain carriers for specific customer segments.

Use cases:

• Free shipping thresholds that appear only when cart value exceeds a specific amount
• Exclusive shipping methods for VIP customers based on tags
• Location-based carrier restrictions (i.e., local delivery only for certain postal codes)
• Rate adjustments based on product weight, dimensions, or cart composition

Shipping Scripts let you build complex fulfillment logic without paying for a shipping calculator app or relying on carrier-provided rates alone.

Payment Scripts

Customize which payment gateways display at checkout based on customer data, cart contents, or order characteristics.

Common implementations:

• Hiding "Buy Now, Pay Later" options for high-risk orders
• Restricting certain payment methods to verified wholesale accounts
• Requiring specific gateways for orders above a threshold
• Showing alternative payment options based on customer location

Payment Scripts ensure you control the checkout experience down to the final transaction method.

Real-World Implementation Examples

Tiered Wholesale Pricing Without an App

Most wholesale apps charge monthly fees and add database queries to your store. With Line Item Scripts, you can implement tiered pricing logic that reads customer tags and applies discounts automatically.

Here's how: Tag wholesale customers with their discount tier (i.e., "Wholesale-20" for 20% off). The Script checks for the tag, reads the discount percentage, and applies it across eligible products. No app, no extra database calls, no monthly subscription.

Conditional Shipping Logic for B2B Orders

B2B customers often need different shipping options than retail buyers. Shipping Scripts can detect business account tags and display freight options, local pickup, or net-terms shipping that regular customers never see.

You can also enforce minimum order thresholds for free shipping based on customer type. Retail customers might need $100 for free shipping, while wholesale accounts qualify at $500.

Capturing Purchase Order Numbers at Checkout

Some businesses require PO numbers for invoice matching. Instead of installing an app to add custom checkout fields, use Scripts to capture this data through cart attributes.

Line Item Scripts can validate that PO numbers are present before allowing checkout completion for tagged business accounts. The data flows directly into order notes, ready for your fulfillment team.

When Scripts Beat Apps Every Time

Apps make sense for visual builders, complex workflows, or functionality requiring ongoing UI updates. But for logic-based customization, Scripts outperform in several ways.

Performance: Scripts execute server-side with no impact on page load times. Apps often inject JavaScript, make API calls, or load external resources that slow down your storefront.

Reliability: Apps depend on third-party servers staying online and maintaining compatibility with Shopify updates. Scripts run on Shopify's infrastructure with no external dependencies.

Cost: Most checkout customization apps charge $20-100/month. Scripts are included with Shopify Plus at no additional cost.

Maintenance: Apps require updates, compatibility checks, and occasional troubleshooting when Shopify changes its API. Scripts written correctly continue running indefinitely.

Conflict avoidance: Every app you install increases the chance of conflicts between integrations. Scripts operate in isolated execution environments, eliminating this risk.

Implementation Considerations

One Script Per Type at a Time

Shopify only allows one active script per category (Line Item, Shipping, Payment). If you need multiple logic sets within one type, you'll need to combine them into a single script with conditional branches.

This limitation forces you to think holistically about your checkout logic rather than layering on fixes incrementally.

Testing Before Publishing

Scripts execute on live transactions, so test thoroughly before activating. Use a private theme with test orders to verify logic works as expected across different scenarios.

Test cases to cover:

• Edge cases like empty carts or single-item orders
• Various customer tag combinations
• Different shipping addresses and cart values
• International vs domestic orders

Script Editor Access

You'll find the Script Editor in your Shopify admin under Apps. From there, you can create new scripts from templates, write custom logic, or modify existing scripts.

Shopify provides starter templates for common scenarios, but you'll likely need custom development for business-specific logic. This is where working with a development partner like Midday makes sense - we build Scripts that execute your exact checkout requirements without app dependencies.

Migration Strategy: Replacing Apps with Scripts

If you're currently using apps for checkout customization, here's how to transition:

Audit your current setup: List every app handling discounts, shipping logic, or payment customization. Document exactly what logic each app provides.

Identify Script-compatible functions: Anything involving conditional pricing, shipping rate adjustments, or payment method filtering can likely move to Scripts.

Build and test in parallel: Create Scripts that replicate app functionality while keeping apps active. Test Scripts thoroughly with a small percentage of traffic before full cutover.

Monitor performance: Track checkout completion rates, average order value, and any customer support tickets related to pricing or shipping after Scripts go live.

Remove redundant apps: Once Scripts handle the logic reliably, uninstall the apps and eliminate those monthly costs.

The Midday Approach to Shopify Scripts

At Midday, we build Scripts as part of comprehensive Shopify Plus implementations. Instead of stacking apps to handle custom logic, we write native Scripts that execute your exact business rules at checkout.

Our process: We map your checkout requirements, identify logic that belongs in Scripts vs custom Liquid code, implement and test thoroughly, then hand over fully documented Scripts you own completely.

No ongoing app subscriptions. No performance overhead. Just clean, efficient code that runs on Shopify's servers and does exactly what your business needs.

Key Takeaways

Shopify Scripts provide native checkout customization that outperforms apps in speed, reliability, and cost. They're server-side, conflict-free, and included with Shopify Plus.

The three Script types - Line Item, Shipping, and Payment - cover most checkout logic scenarios without requiring external integrations.

Smart stores replace apps with Scripts to reduce tech stack bloat, improve performance, and eliminate monthly subscription costs for basic logic functions.

If you're building custom checkout experiences and drowning in app subscriptions, Scripts might be the solution you've been overpaying to avoid.