The G2A Pay Gateway module requires PHP 5.6 or higher, WHMCS 7.x (stable releases only), OpenSSL or equivalent SSL library with TLS 1.1+ support, ionCube Loader v10.1.x or higher, and the PHP extensions cURL with TLS 1.1+, Hash, and OpenSSL. A clear technical understanding of WHMCS addon and gateway management is mandatory along with an approved, active G2A Pay merchant account. These conditions are the only ones validated by our developers. The module may function elsewhere but success is not guaranteed. Your server must already satisfy the official WHMCS system requirements.

These prerequisites exist to guarantee compatibility, prevent runtime errors during payment flows, and maintain security for all transactions. Insufficient TLS support breaks API connectivity to G2A endpoints. Missing the correct ionCube version leaves the encoded module unreadable to PHP. Running pre-release WHMCS builds introduces instability that the gateway does not accommodate. The diagnostic script we provide scans your installation automatically so you can identify and correct gaps before deployment rather than during live payment processing.

#Core System Requirements

Your hosting environment and WHMCS installation must meet the following baseline criteria. Each item has been verified by our team as necessary for reliable module operation.

  • Clear understanding of using WHMCS as well as uploading, installing and configuring addons and gateways. Missteps here frequently cause callback URL or IPN configuration errors after the module files are in place.
  • PHP 5.6 or higher. Older versions lack required language constructs and no longer receive security updates, exposing both the module and your billing system to risk.
  • WHMCS 7.x (we do not support alpha, beta or release candidate builds). Only stable releases ensure the core classes and hooks the gateway depends on remain consistent.
  • OpenSSL (or any SSL library) w/ TLS 1.1+ support. This is mandatory for encrypted outbound connections; weaker configurations trigger handshake failures with G2A services.
  • Ioncube loader v10.1.x or higher. The module ships encoded; this loader version is the minimum that can decode and execute it within PHP.

#PHP Extension Requirements

Beyond the base PHP version and loader, the following extensions must be compiled in and enabled with appropriate feature support.

  • cURL w/ TLS 1.1+ support. The extension handles all HTTP communication with G2A; without current TLS capabilities it cannot complete secure requests.
  • Hash. Provides the hashing algorithms used for signature validation and request integrity checks.
  • OpenSSL. Supplies low-level cryptographic primitives required by the module for encryption and verification tasks.

#G2A Pay Merchant Requirements

A G2A Pay merchant account (approved and ready to accept payments) must be provisioned on the G2A side. Complete their onboarding, verification, and API credential generation processes before entering details into WHMCS. Without live account access the gateway cannot authorize or capture funds regardless of server readiness.

#Using the Requirements Test Script

We offer a PHP script that will quickly and easily check your PHP and WHMCS installation for any missing requirements. The tool can be downloaded here - https://billing.aspnix.com/dl.php?type=d&id=138. Upload it to your WHMCS root, access the file URL in a browser, and review the generated compatibility report. It flags version mismatches, absent extensions, and loader problems in a single pass.

#Usage Steps

  • Download the script and upload it to the root folder of your WHMCS installation via FTP or the file manager.
  • Ensure the script has readable permissions (644) and is accessible via HTTPS.
  • Visit the script URL in your browser to trigger the diagnostic checks.
  • Address every item marked as failed or warning before installing the G2A Pay module.
bash 
php -v
php -m | grep -E 'curl|openssl|hash'

#Common Pitfalls and Best Practices

The most frequent issues are cURL compiled against an old SSL library that lacks TLS 1.1+, an ionCube loader older than v10.1, or running a WHMCS 7.x release candidate. These produce fatal errors on activation or silent failures during checkout. Always cross-check the phpinfo() output for both the core OpenSSL version and the cURL SSL library version. Do not assume that meeting WHMCS minimums automatically satisfies the gateway; the TLS and loader requirements are stricter.

After your environment passes validation, install the module, enter your G2A credentials, and test end-to-end transactions in sandbox mode first. Re-run the diagnostic script after any PHP or WHMCS updates to maintain compatibility. This disciplined approach eliminates most support cases related to gateway activation and payment processing.