I am building a freelancer-style marketplace and need the in-app messaging component produced and integrated. The core platform already covers account creation and job listings; what is missing is a smooth, real-time conversation space that stays inside the site itself. Here is what I need delivered: • A secure, database-backed in-app messaging module that plugs into existing user accounts. • Conversation view showing message history between two parties. • Unread indicators and basic attachment support (images & PDFs). • REST or WebSocket endpoints so the front-end can fetch, send, and update messages without page refresh. • Simple, clean UI built with modern responsive practices and ready to be skinned to match the rest of the marketplace. Acceptance criteria • Users can initiate, read, and reply within a dedicated Messages area. • Messages persist after logout and are visible only to the two participants. • No page reload is required to display new messages. • Code is structured and documented clearly enough for my team to extend later. Please keep the solution lightweight, well-commented, and free of vendor lock-ins so future features such as user profiles or email notifications can be added without major rewrites.