Pre-checkout OTP
Pre-checkout OTP is the pre-purchase verification path. A Cartsaver block lives on your storefront, asks for the customer’s phone number, and verifies it before they ever reach the checkout page. Verifying upfront stops fake COD orders at the source — a shopper without a real phone number never gets to place the order.
Cartsaver presents pre-checkout OTP as one of two verification modes — the screenshot below shows it as the left-hand option in the chooser:
How it works
Section titled “How it works”- The customer adds a product to the cart or visits the product page.
- The Cartsaver storefront block appears asking for their phone number.
- They tap Confirm number — an OTP is sent on the configured channel.
- They enter the code (or auto-verify by tapping the link inside the message).
- The customer is now verified and continues to checkout. If your store also uses Fast Checkout, they land on the single-page Cartsaver-hosted checkout with their country and phone already known.
Verification method
Section titled “Verification method”The pre-checkout flow supports two verification methods, configurable in your Cartsaver pre-checkout settings:
- Template confirmation (default) — the customer taps a button in a Meta-approved WhatsApp template to confirm.
- Numeric code — a one-time code the customer types in.
Choose whichever your Meta template approval and customer base support best.
Channels
Section titled “Channels”Pre-checkout OTP delivers on two channels:
- WhatsApp — recommended for MENA stores.
- SMS — for customers who don’t use WhatsApp.
Configure the channel priority in OTP channels.
Storefront block — Theme App Extension
Section titled “Storefront block — Theme App Extension”The block ships as a Shopify Theme App Extension so install is no-code. Toggle it on from Online Store → Themes → Customize → App embeds.
When it engages
Section titled “When it engages”By default, Pre-checkout OTP engages for Cash on Delivery orders only — that’s where fake-order risk is highest. Extending it to other payment methods is a single setting change.
Plan limits
Section titled “Plan limits”OTP sends draw from your store’s shared WhatsApp and SMS message allowance — no separate per-feature cap for Pre-checkout.
Pairs with
Section titled “Pairs with”- Fast Checkout — the Cartsaver-hosted single-page checkout that replaces Shopify’s native flow for COD orders. Different surface, same goal: fewer drop-offs.
- WhatsApp Order Confirmation — the post-checkout verification alternative for stores that don’t want a storefront block.
Where to configure it
Section titled “Where to configure it”See Pre-checkout blocks for the storefront block setup and OTP channels for channel priority.