SSLCommerz Remote: Multi-Domain Payment Gateway Bridge

🚀 The Challenge: The "Single Domain" Constraint

Many payment aggregators, specifically SSLCommerz, bind a merchant account to a single verified domain. This presents a massive scalability issue for business owners who operate multiple platforms (E-commerce stores, LMS, SaaS) but only possess a single verified merchant identity.

The Problem: How do you accept payments on site-b.com and site-c.com when your gateway is locked to main-site.com?

💡 The Solution: Centralized Gateway Architecture

This plugin transforms a primary WordPress installation into a Centralized Payment Hub. By acting as a secure "Middleware" or "Proxy," it allows any number of external platforms to "borrow" the primary site's SSLCommerz credentials.

How it works:

1. Satellite Sites (WooCommerce, Custom Apps, etc.) send a JSON payload to the Primary Hub via a secure REST API endpoint.
2. The Primary Hub validates the request and initializes the transaction with SSLCommerz.
3. The user completes the payment on the official SSLCommerz hosted page.
4. The Hub captures the IPN (Instant Payment Notification) and securely redirects the user back to the originating Satellite Site with the transaction status.

🗺️ Architecture diagram

sequenceDiagram
    autonumber
    participant Sat as Satellite site
    participant Hub as Primary hub WordPress
    participant C as Customer browser
    participant SC as SSLCommerz hosted page

    Sat->>Hub: JSON payload (REST API)
    Hub->>Hub: Validate request + authorized domain
    Hub->>SC: Initialize transaction (merchant credentials)
    SC-->>C: Redirect to hosted payment page
    C->>SC: Complete payment
    par Asynchronous IPN
        SC->>Hub: Instant Payment Notification (webhook)
    and Return journey
        SC-->>C: Redirect success / fail / cancel
    end
    C->>Sat: Land on per-request return URL with status
    Note over Hub: IPN keeps status in sync if the customer closes the browser

🛠 Technical Highlights

• API-Driven Logic: Built using the WordPress REST API to allow headless integration.
• Platform Agnostic: While built as a WP plugin, the receiving endpoint can handle requests from any framework (Laravel, React, Django, etc.).
• Security: Implements request validation to ensure only authorized satellite domains can trigger the gateway.
• Dynamic Redirects: Intelligent handling of success, fail, and cancel return URLs across different root domains.

⚙️ Key Features

• Zero-Conflict Integration: Enables payment processing for sites that don't meet SSLCommerz's domain verification requirements yet.
• Unified Dashboard: Manage and view transactions from all satellite sites in one central WordPress admin panel.
• Custom Success/Failure Routes: Each request can define where the user returns, allowing for tailored user experiences per site.
• WebHook Support: Robust IPN handling to ensure payment status is synchronized even if the user closes their browser.

🛠 Tech Stack

• PHP (Logic and SSLCommerz API Implementation)
• WordPress Hook System (Custom Settings Pages and Menu)
• REST API (Integration Bridge)
• CURL / Guzzle (For server-to-server communication)

📦 Installation & Setup

1. Download: Clone this repository or download the .zip file.
2. Install: Upload the plugin folder to your primary WordPress directory /wp-content/plugins/.
3. Configure:
   • Navigate to Settings > SSLCommerz Remote.
   • Input your Store ID and Store Password provided by SSLCommerz.
   • (Optional) Whitelist the URLs of your satellite sites for added security.

📈 Impact

• Cost Reduction: Saved the client from the high cost and administrative burden of maintaining multiple merchant accounts.
• Centralized Accounting: Financial data from 3+ websites are now aggregated into one database for easier bookkeeping.
• Faster Go-To-Market: New sites can start accepting payments instantly by simply pointing to the Hub.