WooCommerce Payment Integration + Automated Instance Provisioning (Cross-Server Webhook System)

Overview We're looking for an experienced PHP/WordPress developer to connect our public-facing WordPress website with our separate application backend so that the entire customer journey, from selecting a package to a live instance being provisioned, is fully automated. The architecture is already defined. We need someone to build it cleanly, securely, and reliably. What We Have A fully built WordPress website (no checkout yet) A working PHP/MySQL app backend with an existing instance-creation script (you won't need to rewrite it, just trigger it correctly) A clear architecture diagram and spec we'll share upfront Scope of Work (3 Fixed-Price Milestones) Milestone 1 — WooCommerce E-commerce Setup Install and configure WooCommerce on our existing site, set up our pricing plans as products (recurring subscriptions, monthly/annual), configure WooCommerce Subscriptions, style the checkout to match our existing design, and set up order confirmation emails and customer account pages. Milestone 2 — Payment Gateway Integration Integrate a payment gateway (test + live), configure subscription billing with renewals and failed payment handling, support plan upgrades/downgrades, verify webhook signatures, and fully test across card types and edge cases (declined cards, expired cards, mid-cycle plan changes). Milestone 3 — Webhook + Queue + Automated Provisioning (Core Integration) This is the main custom piece. On the WordPress side: hook into order/subscription events, HMAC-sign a payload, and POST it securely to our app server. Also build a REST callback endpoint to receive the "instance ready" confirmation and notify the customer. On the app server side: build a /api/provision endpoint with HMAC verification, a provisioning queue table with status tracking (pending/in_progress/completed/failed), a cron worker that calls our existing provisioning script, retry/failure logic with alerting, and a success callback to WordPress. Must include full idempotency protection against duplicate webhook deliveries. Deliverable: end-to-end test with a real test payment resulting in an instance being created and the customer notified. Required Skills WooCommerce + WooCommerce Subscriptions development Payment gateway integration (webhooks, subscription lifecycle) PHP REST API development HMAC request signing and signature verification Cron-based job/queue processing Security-conscious practices — this handles real payments and live infrastructure