Opt-ins and toggles, at the right moment.
One checkbox — SMS opt-in, terms, consent or gift-wrap — required or optional.
2 Exactly what your shopper sees — at the moment they're ready to buy.
The Checkout Ninja tag only marks the block in this preview — it never appears in your live checkout.
"Fantastic app, highly recommended. We've been using it for years — a long list of checkout customisations suited to our store. A must-have for all your Shopify checkout needs."
How to add Checkbox to Shopify checkout
Install Checkout Ninja from the Shopify App Store, open the checkout editor, and drag the Checkbox block into the section where you want it. Then configure it in three steps. No theme code, no checkout.liquid, and it survives every Shopify update because it runs on Checkout Extensibility.
Set the label
Write the label exactly as the customer should see it. Use Rich Text inside the label for inline links.
Pick required or optional
Required blocks pay until checked. Optional just captures the state.
Connect downstream (optional)
Wire SMS opt-in to Klaviyo or your SMS tool via Shopify's customer property webhook.
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Can the label contain a link?
Yes. Inline links open in a new tab without disrupting the checkout session.
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Can I require it conditionally?
Yes. Use Conditional Checkbox if you need follow-up fields based on the checkbox state.
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Does the value flow to my ESP?
Yes — via Shopify customer properties. We integrate cleanly with Klaviyo, Mailchimp, Postscript, Attentive.
Build the rest of your checkout.
Conditional Checkbox
Tick a box to reveal more fields — gift options, business and VAT details. No code.
See the block Custom FieldsGift Message
A gift-note field with character count and price-hide — wired into fulfilment.
See the block Custom FieldsText Input
Single-line custom fields with optional validation — saved to the order.
See the blockInstalled by these templates
All templates →Add the Checkbox block today.
Every block + every feature, on a 3-day trial. No card. Live before your next order.