One Page Checkout for OpenCart 2.3, 3.x and 4.x

What the buyer sees

Stock OpenCart checkout is split into steps: checkout option, address, shipping, payment, and every step has to be expanded and confirmed. The buyer never sees how much is left, and every step is a chance to close the tab.

The module puts the same steps on one page. Contact details, address, shipping and payment methods, the comment box and the order summary are all visible at once. As soon as the buyer leaves a field and the required ones are filled, the module saves the data, quotes shipping and pulls payment methods by itself.

By default the page selects guest checkout and hides the password field. Anyone who wants an account switches back with one click.

What the admin gets

Orders land in the normal OpenCart list, with the same statuses, invoices and e-mails. No separate table and no custom format — the module does not create the order itself, the core does.

How it works step by step

1. The buyer hits checkout in the cart. With “Replace stock checkout” on, OpenCart redirects to the module page; otherwise the page lives at its own URL and the stock one stays untouched.

2. The buyer fills in contact details and the address. The module watches the fields and saves them through the core route as soon as the required ones are complete.

3. Shipping methods appear right after that, with real rates from your own shipping extensions.

4. Payment methods follow the same way. If there is only one, the module selects it.

5. At the bottom sits the confirm block with the button drawn by the payment extension itself. That is why gateways with their own confirmation or 3-D Secure step keep working.

Under the hood

The module does not rewrite the checkout. The page assembles the native OpenCart blocks and runs the same core routes the stock checkout uses. checkout/confirm creates the order, the payment extension draws its own button.

That is why third-party shipping and payment extensions need no special support: the core hidden fields stay in the markup, so branch pickers keep writing into them. No core files are patched — events on 4.x and 3.x, ocmod on 2.3.

How to install

OpenCart 4.x: Extensions → Installer → Upload → pick the zip → press “+” in the list. Then Extensions → Modules → One Page Checkout → Edit → enable and save.

OpenCart 3.x: the same through Extensions → Installer, then Extensions → Modules → Install → Edit.

OpenCart 2.3: the stock installer only works over FTP, so upload the contents of upload/ to the shop root manually. Then run Extensions → Modifications → Refresh, otherwise the cart button will not switch to the new page.