Petpooja-Style POS App

I’m putting together a restaurant POS modeled closely on the Petpooja experience, and I need the backbone of the system built right away. Your task is to create clean, well-documented PHP APIs that my mobile and web teams can plug into immediately.

Scope of the APIs
• Core focus: real-time inventory management—stock levels, item variations, automatic deductions after each sale, low-stock alerts, and simple purchase-order generation.
• Seamless sales and transaction hooks so that, when I’m ready, we can extend the same codebase to cover billing, reporting, and customer data without rewriting everything.
• Secure authentication, role-based access, and clear JSON responses are mandatory so integration stays painless.
• MySQL (or MariaDB) is preferred for the data layer, but I’m open to Postgres if you can justify the gain.

Acceptance criteria
1. Endpoints return the exact data structures we agree on in the signed-off Swagger / OpenAPI spec.
2. Response times stay under 300 ms on a modest VPS.
3. A Postman collection and a quick-start read-me let another developer get the system running in under 15 minutes.

The deadline is ASAP, so I’ll review partial deliveries as you complete each functional chunk. If you’ve built POS or large inventory modules before, especially in PHP-7+ with modern frameworks (Laravel, Symfony, Slim, etc.), that’s a big plus—just point me to a repo or a live demo and we can get started.