BigCommerce

We have not shipped a BigCommerce install. This is the shape we would expect, and the specific things we would confirm with you, starting with whether a script on your order-confirmation page can carry the redemption card.

Not done: no BigCommerce store has been through a real install

Nothing on this page is a report from a live install. It follows from how the tag behaves, not from anything we have watched it do on BigCommerce. Treat every "likely" below as a question, not a promise. The two platforms we have proven end to end are Shopify and custom / headless; where we stand puts all six in one table.

What we can tell you without hedging is how the tag itself behaves. Nothing in it is BigCommerce-specific, and only one path in it is Shopify-specific: the cart-attribute writer, which is off unless you are on Shopify with the order-email channel enabled. Page detection, the three cart adapters, the click id, the claim URL and the gwp:selection hook are all platform-neutral. That is why we can describe the shape below with some confidence, and still not claim we have walked it.

The shape we would expect

Tag placement	Likely Script Manager (a script applied to all pages) or the Stencil theme's base layout. Script Manager also has a checkout/order-confirmation scope. Whether a script there can carry the redemption card is the first thing we would test together
Adapter	Likely dom against the cart total element; datalayer if you run GTM with an ecommerce data layer
Page detection	*/cart.php is already in our default basket patterns, so a stock BigCommerce cart path resolves without configuration
Claim moment	To confirm. If a script can run on your order-confirmation page, the on-page card works as it does on custom platforms. If not, the generic hook plus your own order-confirmation email is the path (the same shape as Shopify, but with your email platform instead of a Liquid template)
We would confirm	Whether Script Manager can inject on the order-confirmation page; a stable selector for the cart total; whether your cart page updates totals over AJAX without a URL change

Where next

• What to bring to that conversation. Three answers get an unproven platform scoped in a single call. Bring a staging URL if you have one; the tag runs there as soon as the hostname is registered.
• Shopify: a platform we have actually installed, written up end to end. The best way to judge the size of the job.
• Install the tag, the platform-agnostic guide: snippet, page registration, adapters, verification, troubleshooting and CSP.
• Ask us something. Email support@gwpingenuity.com with [INTEGRATION] in the subject, saying you are on BigCommerce. We would rather scope it than have you find the gaps. (/support is the shopper help page, not developer support.)