I need a clean, well-documented API that powers my digital-signage ecosystem for TVs and video walls while remaining fully controllable by voice. The system must register each device, recognise its playback mode (USB, online cloud, or hybrid), sync new content automatically, and keep everything running locally even when the network drops. Three web portals sit on top of the API: • Admin panel – handles user management, content management, and rich analytics/reporting so I can track device health and playback statistics. • Dealer panel – lets dealers create reusable templates, assign them to their clients’ screens, and review client performance. • Client panel – allows end users to see the templates they have been given, upload fresh media, and pull down usage reports. Key workflow The Admin builds a template → Dealer assigns it to a client plan → the client uploads or schedules content → the API pushes the assets to the chosen mode (cloud, USB, or hybrid) → each device stores the files locally and plays them, while voice commands can pause, replace, or request reports at any time. Technical expectations REST (or GraphQL) endpoints with JWT/OAuth security, real-time updates via WebSocket or SSE, a straightforward schema for templates/playlists, and hooks for major voice assistants (Google Assistant/Alexa). Clear Swagger/OpenAPI documentation is essential so my in-house team can maintain it later. Acceptance criteria • API endpoints cover all panel functions and device operations • Seamless content sync in every mode, with offline playback resilience • Voice commands trigger core actions and surface analytics • Source code, database schema, and setup scripts delivered in a Git repo • Post-handover support for deployment guidance If this scope matches your expertise, I’m ready to move quickly.