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SureCart provides multiple ways to add items to the cart programmatically:
  1. URL Parameters - Redirect users to checkout with pre-filled line items
  2. Shortcodes - Use built-in shortcodes for add-to-cart buttons
  3. Checkout Form Customization - Add custom fields, checkboxes, or content
For a complete reference of available hooks, see the Cart Hooks and Checkout Hooks documentation.

​
URL Parameters

The most straightforward way to add items to cart is by redirecting users to the checkout page with line_items query parameters.

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Basic Example

<?php
$checkout_url = add_query_arg(
    [
        'line_items' => [
            [
                'price_id' => 'price_xxxxxxxxxxxxx', // Your SureCart price ID
                'quantity' => 1,
            ],
        ],
    ],
    \SureCart::pages()->url( 'checkout' )
);
?>

<a href="<?php echo esc_url( $checkout_url ); ?>">
    Add to Cart
</a>

​
Multiple Items

<?php
$checkout_url = add_query_arg(
    [
        'line_items' => [
            [
                'price_id' => 'price_product_one',
                'quantity' => 1,
            ],
            [
                'price_id' => 'price_product_two',
                'quantity' => 2,
            ],
        ],
    ],
    \SureCart::pages()->url( 'checkout' )
);
?>

​
With Coupon Code

<?php
$checkout_url = add_query_arg(
    [
        'line_items' => [
            [
                'price_id' => 'price_xxxxxxxxxxxxx',
                'quantity' => 1,
            ],
        ],
        'coupon' => 'SAVE10', // Promotion code
    ],
    \SureCart::pages()->url( 'checkout' )
);
?>

​
With Product Variant

<?php
$checkout_url = add_query_arg(
    [
        'line_items' => [
            [
                'price_id'   => 'price_xxxxxxxxxxxxx',
                'quantity'   => 1,
                'variant_id' => 'variant_xxxxxxxxxxxxx', // Optional variant
            ],
        ],
    ],
    \SureCart::pages()->url( 'checkout' )
);
?>

​
Shortcodes

SureCart provides built-in shortcodes for adding products to cart.

​
Add to Cart Button

[sc_product_cart_button id="prod_xxxxxxxxxxxxx" text="Add To Cart"]
​
Parameters
Shortcode Parameters

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Buy Button with Line Items

[sc_buy_button]
    [sc_line_item price_id="price_xxxxxxxxxxxxx" quantity="1"]
[/sc_buy_button]

​
Multiple Line Items

[sc_buy_button]
    [sc_line_item price_id="price_product_one" quantity="1"]
    [sc_line_item price_id="price_product_two" quantity="2"]
[/sc_buy_button]

​
Using Shortcodes in PHP

You can render shortcodes programmatically in PHP using WordPress’s do_shortcode function. 
<?php
echo do_shortcode( '[sc_product_cart_button id="prod_xxxxxxxxxxxxx" text="Buy Now"]' );
?>
For buy buttons with multiple line items: 
<?php
echo do_shortcode( '
    [sc_buy_button]
        [sc_line_item price_id="price_product_one" quantity="1"]
        [sc_line_item price_id="price_product_two" quantity="2"]
    [/sc_buy_button]
' );
?>

​
Checkout Form Customization

Add custom fields, checkboxes, or content to checkout forms using the render_block filter. This example walks you through adding a terms checkbox with server-side validation.
1

Add custom content before the submit button

Use the render_block filter to inject HTML before any checkout block. Target the block by checking $block['blockName'].
add_filter( 'render_block', function( $block_content, $block ) {
    if ( 'surecart/submit' !== $block['blockName'] ) {
        return $block_content;
    }

    $checkbox = '<div class="my-terms-checkbox" style="margin-bottom: 1em;">
        <label style="display: flex; align-items: start; gap: 0.5em; cursor: pointer;">
            <input type="checkbox" name="accept_terms" value="yes" required />
            <span>I agree to the <a href="/terms" target="_blank">terms and conditions</a></span>
        </label>
    </div>';

    return $checkbox . $block_content;
}, 10, 2 );
2

Add server-side validation

Validate custom fields using the surecart/checkout/validate filter. Return errors to prevent checkout submission.
add_filter( 'surecart/checkout/validate', function( $errors, $args, $request ) {
    // phpcs:ignore WordPress.Security.NonceVerification.Missing
    $accept_terms = isset( $_POST['accept_terms'] ) ? sanitize_text_field( wp_unslash( $_POST['accept_terms'] ) ) : '';

    if ( 'yes' !== $accept_terms ) {
        $errors->add( 'terms_required', 'You must accept the terms and conditions.' );
    }

    return $errors;
}, 10, 3 );
See Checkout Hooks for more validation examples.

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Checkout Block Names

Block NameDescription
surecart/submitSubmit/Pay button
surecart/emailEmail field
surecart/nameFull name field
surecart/first-nameFirst name field
surecart/last-nameLast name field
surecart/phonePhone number field
surecart/addressAddress fields
surecart/paymentPayment method selection
surecart/couponCoupon code field
surecart/line-itemsOrder line items
surecart/totalsOrder totals summary

Cart Hooks

Customize cart icon, visibility, and behavior.

Checkout Hooks

Hook into checkout events and customize validation.