Architecture¶

System Overview¶

┌─────────────────────────────────────────┐
│            cast2md Server               │
│                                         │
│  ┌──────────┐  ┌───────────────────┐    │
│  │ Web UI   │  │ REST API          │    │
│  └──────────┘  └───────────────────┘    │
│  ┌──────────┐  ┌───────────────────┐    │
│  │ Workers  │  │ PostgreSQL + pgvec│    │
│  └──────────┘  └───────────────────┘    │
└────────────────────┬────────────────────┘
                     │
        ┌────────────┼────────────┐
        │            │            │
   ┌─────────┐ ┌─────────┐ ┌─────────┐
   │ Node A  │ │ Node B  │ │ RunPod  │
   │ M4 Mac  │ │ GPU PC  │ │ A5000   │
   └─────────┘ └─────────┘ └─────────┘
         (optional remote workers)

Components¶

Server -- FastAPI application with web UI, REST API, and background workers
PostgreSQL -- database with pgvector extension for semantic search
Workers -- download workers and local transcription worker run in the server process
Remote nodes (optional) -- additional machines for distributed transcription
RunPod (optional) -- on-demand GPU pods for batch processing

Interfaces¶

Interface	Description
Web UI	Manage feeds, view episodes, search transcripts
CLI	Command-line tool for all operations
REST API	Full API for automation and integration
MCP Server	Claude integration via Model Context Protocol

Transcription Backends¶

Backend	Use Case	Languages	Speed
Whisper (faster-whisper)	Local CPU/GPU transcription	99+ languages	Varies by model
Whisper (mlx-whisper)	Apple Silicon Macs	99+ languages	Fast on M-series
Parakeet	RunPod GPU pods	25 EU languages	~100x realtime