README.md

Clientexec Plugin Development Kit

A reference kit for building, converting, and modernizing Clientexec plugins, written so it works equally well for human developers and for AI coding tools.

Written for Clientexec 7.3. Plugins built from it rely on 7.3 behavior and should state 7.3 as their minimum supported version.

Two ways to use it

1. Portable context (any AI tool). Everything under reference/ is plain Markdown. Give the file for the plugin type you're working on to Cursor, Copilot, ChatGPT, Claude, or any other tool, along with reference/common/conventions.md, then ask it to build or convert a plugin. If you're porting from WHMCS, also include the matching convert-from-whmcs.md.
2. Claude Code skill. This folder is also a skill. SKILL.md routes to the right reference on demand. Copy or symlink the folder into your Claude Code skills directory (for example ~/.claude/skills/clientexec-plugin-dev-kit) and invoke it from Claude Code.

Layout

clientexec-plugin-dev-kit/
├── SKILL.md                         # skill router (also a human index)
├── README.md                        # this file
└── reference/
    ├── common/
    │   └── conventions.md           # shared rules: naming, layout, settings, errors, logging, HTTP, views, style
    ├── server/
    │   ├── create.md                # author a new server (provisioning) plugin, with a complete example
    │   └── convert-from-whmcs.md    # port a WHMCS provisioning module to a Clientexec server plugin
    ├── gateways/
    │   ├── create.md                # author a new payment gateway, with a complete offsite example
    │   └── convert-from-whmcs.md    # port a WHMCS payment gateway module to a Clientexec gateway
    ├── registrars/
    │   ├── create.md                # author a new registrar plugin, with a complete example
    │   └── convert-from-whmcs.md    # port a WHMCS registrar module to a Clientexec registrar
    ├── snapins/
    │   ├── create.md                # author a new snapin: pages, hook locations, AJAX, events, with a complete example
    │   ├── events.md                # every event Clientexec fires and the data it passes
    │   └── convert-from-whmcs.md    # port a WHMCS addon module or hooks file to a snapin
    ├── invoices/
    │   └── create.md                # author a PDF invoice template
    ├── phoneverification/
    │   └── create.md                # author a phone verification plugin, with a complete example
    ├── ssl/
    │   └── create.md                # author an SSL certificate reseller plugin
    ├── import-export/
    │   └── create.md                # author import plugins (migrations and custom importers) and export plugins
    ├── captcha/
    │   └── create.md                # author a new captcha plugin, with a complete example
    ├── fraud/
    │   └── create.md                # author a new fraud screening plugin, with a complete example
    ├── services/
    │   └── create.md                # author a new scheduled service, with a complete example
    └── twofactor/
        └── create.md                # author a new two-factor authentication plugin, with a complete example

Scope today

• Server plugins: full method surface of ServerPlugin, the $args structure, settings and per-package fields, actions and client actions, single sign-on, client area views and panels, resellers, a complete example plugin, and a WHMCS porting guide.
• Payment gateways: offline, offsite, onsite form, and stored payment method gateways; the full $params set, return contract, the Plugin result recorder, callbacks, settings core reads, payment verification rules, a complete offsite example with a webhook, and a WHMCS porting guide.
• Registrars: every method core calls, with the exact $params and return shapes core expects; domain search and name suggest, register/renew/transfer, nameservers, DNS, contacts, lock, domain and price import, automatic renewal, and a complete example.
• Snapins: admin and client area pages, hook locations, admin and client area AJAX, access control, event listeners, the full event catalog, a complete example, and a WHMCS addon module and hooks porting guide.
• SSL certificates: certificate type mapping, the package fields a plugin reads and writes, purchase, status and CSR parsing, and invite URL providers.
• Phone verification: when core triggers it, what it handles, and a complete SMS example.
• Invoice templates: how templates are chosen and rendered by mPDF, every variable a template receives, and escaping.
• Import and export: migration importers and the import format (sections, column order, value formats, pricing), custom importers, export plugins, and a CSV export example.
• Fraud: when checks run and what a rejection does, the method sequence and what each receives and returns, IP banning, a complete example, and a WHMCS mapping.
• Captcha: which forms use it, view() and verify(), a complete example.
• Services (scheduled tasks): how the runner schedules and locks runs, execute() results and error emails, keeping state between runs, dashboard summaries and pending items, a complete example, and a WHMCS cron hook mapping.
• Two-factor authentication: what fits the plugin type, enrollment and verification contracts, how the active plugin is chosen, a complete example, and a WHMCS mapping.
• Shared conventions: the rules every plugin type follows.