I built a custom WordPress booking and billing plugin that ties together a REST-style API, a PHP back-end, and a JavaScript calendar interface. The core functionality works, yet several critical pieces still misbehave and I need an expert to bring the whole platform to production-ready quality. Current pain points • Dynamic pricing crashes or throws intermittent errors, especially when multiple modifiers are stacked. • The booking flow feels clunky; the UI needs polishing and the error handling / validation must be rock-solid so users never end up with half-saved reservations. • Cancellation logic is in place but still demands a thorough audit to be absolutely reliable. - The system also generates reports i.e. monthly room bookings (for users to track bookings), monthly room bookings, occupancy, sales revenue, by day, week, month, annual for all rooms and also by individual user, however this is also clunky to navigate and the data is unreliable. The codebase is 100 % custom—no off-the-shelf theme tricks—so you’ll be working with bespoke PHP classes, WordPress hooks, custom database tables, and vanilla JS (no heavy frameworks). I expect clean, well-commented solutions that respect existing architecture while refactoring where technical debt is hurting stability. Deliverables 1. Debug and stabilise the dynamic pricing engine so it calculates correctly under every rate rule without crashing. 2. Refactor front-end booking and reports screens: improve the calendar, booking process, and reports screens UI and inject robust client- & server-side validation. 3. Audit API endpoints and database queries to guarantee data integrity for bookings, reports both user and admin, invoices, and cancellations. 4. Tighten cancellation routines: confirm that refunds, availability resets, and admin/user notifications execute consistently. 5. Provide a concise hand-over report summarising fixes, updated files, and any new database schema changes. If you live and breathe WordPress internals, custom post types, REST controllers, and complex pricing algorithms, I’m ready to share the repository and staging credentials so we can get started right away.