Smart checkout
rules.

Enforce business rules without adding friction. We build validation functions that verify age, validate addresses, prevent fraud, enforce limits, and ensure compliance—all while keeping checkout smooth.

See Capabilities

Rules that
protect you.

Validation functions let us enforce business rules, compliance requirements, and fraud prevention at checkout.

Age Verification

Require age confirmation for restricted products. Collect birthdate, checkbox confirmation, or integrate with verification services.

Address Validation

Verify shipping addresses against postal databases. Catch typos, suggest corrections, and prevent delivery issues.

Cart Quantity Limits

Enforce minimum or maximum quantities per product, per category, or per order. Prevent bulk buying or meet minimum order requirements.

Fraud Prevention Rules

Block suspicious orders based on patterns, velocity, or risk signals. Require additional verification for high-risk purchases.

Business Policy Enforcement

Ensure compliance with your business rules. Product restrictions, customer eligibility, or promotional terms.

Geographic Restrictions

Block orders or specific products to certain regions. Comply with export rules, licensing restrictions, or shipping limitations.

Promotional Validation

Enforce discount code rules beyond native capabilities. Usage limits, product exclusions, or customer segment requirements.

Data Quality Checks

Validate phone numbers, email formats, or custom fields. Ensure clean data collection at checkout.

Inform and
protect.

Checkout notices that communicate important information to customers.

Checkout Notice checkout block example

Checkout Notice

Display important checkout notices

Customs Duties Notice checkout block example

Customs Duties Notice

Customs and tax guarantees

Shipping Note checkout block example

Shipping Note

Important shipping information

Protection that
works.

See how validation functions prevent problems and ensure compliance.

Regulatory Compliance

An alcohol retailer implements age verification at checkout with birthdate collection and legal disclaimers. Result: 100% compliance with alcohol delivery regulations.

Prevent Reseller Abuse

A limited-edition sneaker brand limits purchases to 2 per customer with address matching. Result: 80% reduction in reseller purchases.

Reduce Failed Deliveries

A DTC brand validates addresses against USPS database and flags PO boxes for physical goods. Result: 60% reduction in address-related returns.

Stop Fraudulent Orders

An electronics retailer blocks orders with mismatched billing/shipping or from high-risk regions. Result: 70% reduction in chargebacks.

Powered by
Shopify Functions.

Validation runs on Shopify Functions—serverless logic that executes in under 5 milliseconds, directly within Shopify's infrastructure, for zero latency impact.

Shopify Functions

  • Cart Validation Function
  • Checkout Validation Function
  • Sub-millisecond execution (< 5ms)
  • WebAssembly runtime
  • Rust or JavaScript development
  • Automatic scaling

Available Data

  • Cart contents and line items
  • Customer information and tags
  • Shipping and billing addresses
  • Cart attributes
  • Product metafields
  • Customer metafields
  • Discount codes applied

Validation Actions

  • Block checkout with error message
  • Show warning messages
  • Require field input
  • Redirect to specific page
  • Log for fraud review
  • Trigger additional verification

Ready to customize
your checkout?

Tell us about your Shopify Plus store and the checkout experience you want to create. We'll discuss what's possible with Checkout Extensibility and how we can help.

Free initial consultation Shopify Plus only Custom solutions

Or email us directly: hello@thecheckoutagency.com