Paddle Billing for WHMCS

The only WHMCS payment gateway you need for Paddle. Accept one-time payments and recurring subscriptions through Paddle's beautiful overlay checkout — fully automated, fully integrated, zero hassle.

Why Paddle Billing for WHMCS?

Paddle is more than a payment processor — it's a Merchant of Record that handles global tax compliance, fraud protection, and payment methods in 200+ markets. This module brings all of that power directly into your WHMCS billing platform with a seamless, plug-and-play integration.

Stop losing customers to broken checkout flows. Paddle's overlay checkout keeps buyers on your site, supports cards, PayPal, Apple Pay, Google Pay, and dozens of local payment methods — all with a single integration.

Key Features

Automated Invoice Payments

When a customer pays through Paddle, the webhook listener automatically marks the WHMCS invoice as Paid — no manual intervention needed. Your invoices stay in sync with Paddle in real-time.

Intelligent Subscription Handling

The module automatically detects recurring services and maps them to Paddle subscriptions with the correct billing cycle. Monthly, quarterly, semi-annually, annually — all handled automatically. When WHMCS generates a renewal invoice, the subscription payment is matched and applied instantly.

Smart Mixed-Cart Processing

Got a customer ordering a monthly hosting plan with a one-time setup fee and a promo discount? Most gateways break. This one doesn't. The module intelligently splits mixed carts, applies dynamic inline discounts for the first payment, and locks in the true recurring price for future renewals.

Full and Partial Refunds

Issue refunds directly from WHMCS — no need to log into Paddle separately. Click the Refund tab on any paid invoice, enter the amount, and the module instantly processes it through Paddle's Adjustments API. Supports both full refunds and partial refunds down to individual line items.

Automatic Subscription Cancellations

When a client requests cancellation or WHMCS terminates an overdue service, the module immediately sends a cancellation signal to Paddle. The underlying billing agreement is terminated instantly — your customer is never accidentally charged after their service ends.

Native Paddle Tax Calculations

Choose exactly how Paddle handles tax on your prices:

• Sync with Paddle Dashboard — uses your global Paddle tax settings
• Automatic based on location — Paddle calculates tax dynamically by buyer country
• Price includes tax — tells Paddle your WHMCS totals already include tax
• Price excludes tax — Paddle adds tax on top of your price

Secure Webhook Verification

Every incoming webhook is verified using HMAC-SHA256 signature validation before any action is taken. No unsigned or tampered requests can trigger invoice payments or status changes.

Admin Webhook Logs

View the raw data of every webhook Paddle sends to your server from within WHMCS. Navigate to Addons > Paddle Billing Addon to inspect, debug, and verify your payment flow.

How It Works

1. Customer clicks Pay Now on a WHMCS invoice
2. Paddle's overlay checkout opens on your page — no redirects
3. Customer pays with their preferred method (card, PayPal, wallet, etc.)
4. Paddle sends a transaction.paid webhook to your WHMCS
5. The module verifies the signature and marks the invoice as Paid
6. For subscriptions, future renewals are charged and applied automatically

Quick Setup

1. Upload the module files to your WHMCS installation
2. Activate Paddle Billing under System Settings > Payment Gateways
3. Enter your Paddle API Key, Client-Side Token, and Webhook Secret
4. Configure your preferred checkout theme and tax settings
5. Start accepting payments

Setup takes less than 5 minutes. Full documentation included.

Requirements

• WHMCS 8.x or later
• PHP 7.4+ or 8.x with cURL extension
• A Paddle Billing account (not Paddle Classic)
• SSL/HTTPS enabled on your WHMCS installation

What You Get

• Gateway Module — checkout, refunds, cancellations, tax sync
• Webhook Listener — automated payment processing with signature verification
• Admin Addon — webhook logs and debugging tools
• Full Documentation — step-by-step setup guide with screenshots

Built for hosting businesses that want reliable, automated billing with Paddle. No complicated setup. Just install, configure, and let it handle the rest.