The Public Pay Addon module for WHMCS requires a precise combination of server software, PHP configuration, and WHMCS settings to run reliably and securely. Our developers have tested and support the module exclusively under the conditions outlined below. It may operate in other environments, but we cannot guarantee functionality or provide support outside these parameters. All guidance here assumes your base server and PHP setup already satisfies the official WHMCS system requirements.

These constraints exist primarily to guarantee secure TLS communications with payment networks, accurate handling of currency arithmetic, and stable execution of the encoded module code. Missing components typically surface as fatal PHP errors, failed API calls to gateways, or silent transaction processing failures.

#Core System Requirements

The following baseline components must be present and operational on your server. Each has been verified by our team during module development and QA cycles.

  • Clear understanding of using WHMCS as well as uploading, installing and configuring addons and gateways. Administrators without this foundation will struggle to deploy the module or diagnose integration issues with payment flows.
  • PHP 5.6 or higher. This minimum version supplies language features and security updates required by the module and by current external payment service endpoints.
  • WHMCS 7.x (we do not support alpha, beta or release candidate builds). Production releases only are tested; pre-release WHMCS versions introduce breaking changes that invalidate module compatibility.
  • OpenSSL (or any SSL library) w/ TLS 1.1+ support. Modern payment gateways refuse connections using deprecated SSL or early TLS versions; this requirement prevents handshake failures during transaction posting.
  • Ioncube loader v10.1.x or higher. The module is delivered encoded; an incompatible or absent loader produces a blank page or a loader-specific fatal error on every request.

#PHP Extension Requirements

The module depends on the following compiled PHP extensions. These are commonly available but must be explicitly enabled in your php.ini and verified as active.

  • Bcmath* – supplies arbitrary-precision math functions used for all monetary calculations to prevent floating-point rounding errors.
  • cURL w/ TLS 1.1+ support – handles every outbound request to PayPal, Coinbase, and related verification endpoints.
  • GMP* – an alternative library for large-integer arithmetic that can substitute for BCMath in financial operations.

Either BCMATH or GMP extension is required, both extensions are not required. The module automatically selects the available library at runtime. Absence of both produces immediate fatal errors on any payment-related action.

#WHMCS Configuration Requirements

Beyond server software, the following items inside WHMCS must be prepared before the addon can process payments. The module acts as an extension to existing gateway functionality rather than a standalone processor.

  • An understanding of WHMCS addons, modules and gateways and how to install and configure them. This knowledge is a prerequisite for activation and for mapping the addon to the correct invoice and transaction workflows.
  • WHMCS built-in PayPal payment gateway activated and configured. This serves as the default transaction path for the majority of installations.
  • ASPnix Coinbase Payment Gateway module – Activated and configured (optionally required for Coinbase payments). The Public Pay Addon will not initialize without at least one supported gateway present and enabled.

#Testing Your Environment

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 the file to the root of your WHMCS installation, then browse to it directly (example: https://yourdomain.com/check.php). The report lists every checked item with pass/fail status and provides direct guidance on remediation steps for any failures.

Common pitfalls include an outdated ionCube loader after a PHP upgrade, cURL compiled without recent TLS support, and payment gateways left in test mode or with invalid API credentials. Re-run the test script after each change to confirm resolution. The script also surfaces version mismatches that might not produce obvious errors until a live transaction is attempted.

Once your environment meets all listed requirements, proceed with module installation and gateway mapping. Verify end-to-end transaction processing in sandbox mode before enabling on production invoices.