Custom Gateway Integration for WooCommerce

I have a WooCommerce store running on WordPress and I need one clean, reliable way to collect one-time payments through a gateway that is not natively supported. I am open to any technical route—extending an existing plugin, forking WooCommerce’s sample gateway, or building a lightweight stand-alone plugin—as long as the finished solution installs like a normal WordPress plugin, activates without errors, and works seamlessly in the checkout flow.

Key points
• WordPress + WooCommerce are already live.
• Only one-time charges are required; no subscriptions or recurring billing logic is necessary.
• Gateway credentials, API docs, test keys, and a staging site will be provided as soon as the project starts.

Acceptance criteria
1. Customers see the new payment option at checkout and can complete a test order in sandbox mode.
2. Orders move to “Processing” (or another status we agree on) after a successful callback/WEBHOOK.
3. Failed or cancelled transactions revert stock and show the correct notice to the buyer.
4. Code follows WooCommerce standards (wp_nonce verification, settings tab, translation-ready strings).
5. A short readme explains installation, configuration fields, and how to switch between sandbox and live mode.

Skills that usually make this quick: PHP 8+, WordPress hooks/filters, WooCommerce Payment Gateway API, REST/JSON, webhooks, and basic front-end JS for tokenization if the provider requires it.

Once it works flawlessly on staging, I will move it to production and run a real transaction for final confirmation.