WooCommerce E-commerce App Integration

I need a WooCommerce-based web application that goes beyond the typical store setup. The project covers three main layers: custom functionality, rock-solid automated testing on the back end, and clean integrations with several external APIs (inventory, shipping and a payment gateway).

Scope
• Build or extend a WooCommerce plugin/theme that delivers the niche features I will share in a detailed spec.
• Expose and consume REST endpoints so the shop can sync stock and order data in real time with third-party services.
• Create PHPUnit (or similar) test suites that cover critical business logic, edge cases and security. Continuous integration via GitHub Actions or GitLab CI should run these tests on every push.
• Produce concise, developer-friendly documentation covering setup, environment variables, and sample API calls.

Acceptance Criteria
1. All user flows—browse, add to cart, checkout, refunds—work flawlessly in the latest versions of Chrome, Firefox and Safari.
2. Automated tests reach at least 90 % code coverage for the custom code base and pass in the CI pipeline.
3. External APIs respond within agreed SLAs; failures must fall back gracefully with logged errors.
4. Code follows PSR-12 standards and is committed to a private Git repository I will provide.
5. Final delivery includes a staging site link for live verification and a hand-off call or recorded walkthrough.

Tech Stack Hints
WooCommerce, WordPress, PHP 8+, MySQL, REST/JSON, OAuth2 or token-based auth, Docker for local parity, Postman/Insomnia for API testing.

If you have questions about the data sources, response formats or deployment environment, let me know early so we can lock them down before development starts.