Order Form Overview
The HmSingleOrderAddon checkout replaces the standard WHMCS multi-page order wizard with a streamlined single-page experience. This page explains how the form is structured and how a customer moves through it.
Entry Points
Customers reach the order form via:
| URL | Description |
|---|---|
https://yourdomain.com/checkout.php | Standalone — full-page branded checkout, no WHMCS header/footer |
https://yourdomain.com/hmorder.php | WHMCS-styled — uses the active WHMCS client area template |
Most stores link product “Order Now” buttons directly to:
https://yourdomain.com/checkout.php?a=add&pid={productId}
Form Structure
The single-page checkout is divided into logical sections displayed vertically on one page:
1. Product Summary
The top section shows the product the customer is about to order:
- Product name and description
- Billing cycle selector (monthly, quarterly, annually, etc.)
- Price for the selected cycle
- Any promotional discounts applied
2. Domain Configuration
If the product requires a domain (set in WHMCS product settings), the domain section appears below the product summary:
- Register a new domain — live availability search
- Transfer a domain — enter an existing domain + EPP/auth code
- Use an existing domain — enter a domain the customer already owns
Info
Domain pricing is pulled from your WHMCS domain registrar pricing configuration. Only TLDs you have priced and enabled in WHMCS will appear in the TLD selector.
3. Configuration Options
If the product has configurable options (add-ons, control panels, OS choices, etc.) they appear as an inline panel below the domain section. Customers make their selections here without leaving the page.
4. Customer Details
New customers fill in account details (name, email, password, address). Existing customers log in, and the form pre-fills their information.
5. Billing & Payment
The final section shows:
- Order summary with itemized pricing (product + domain + config options)
- Applied discounts / promotions
- Tax amount
- Total due today
- Payment gateway selector
- Payment form (card fields, PayPal redirect button, etc.)
6. Order Confirmation
After successful payment or order placement, the customer is shown a confirmation message and redirected to the WHMCS client area or a custom URL.
Navigation Flow
Unlike the default WHMCS checkout, there are no separate pages. Sections load inline:
- Customer lands on the product order URL
- All sections are visible/expandable on one page
- Customer completes sections top to bottom
- Clicking the payment button submits the full order
No reloads
The form uses AJAX for domain availability checks and configuration option updates — customers never leave the page during the ordering process.
Mobile Experience
The order form is fully responsive. On mobile:
- Sections stack vertically (same order as desktop)
- The billing cycle selector becomes a scrollable pill-button row
- The domain TLD selector collapses to a dropdown
Checkout URL Parameters
You can deep-link to a specific product using URL parameters:
| Parameter | Description | Example |
|---|---|---|
pid | Pre-select a product by ID | ?a=add&pid=5 |
billingcycle | Pre-select a billing cycle | ?billingcycle=annually |
promocode | Pre-apply a promo code | ?promocode=LAUNCH20 |
currency | Force a currency | ?currency=2 |
Example full URL:
https://yourdomain.com/checkout.php?a=add&pid=5&billingcycle=annually&promocode=LAUNCH20