Architecture

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Stamon is a Rust workspace and a Svelte frontend, built into one Docker image.

Crates

Crate	Does
`crates/server`	The HTTP API and WebSocket (axum), SQLite storage (sqlx) and background jobs (apalis)
`crates/checks`	Check types: the `CheckConfig` enum and one module per type
`crates/alerts`	Notification channels: the `ChannelConfig` enum and one module per channel
`crates/ssl-exp`	Reads certificate expiry dates for TLS checks

Server modules

Module	Does
`routes`	API handlers, nested under `/api`
`auth`, `extractors`	Tokens, role checks and request parsing
`models`	Database queries, one file per table
`service`, `monitors`	The scheduler and worker registration
`job`	The check job (`job/monitor`) and alert delivery (`job/alert.rs`)
`ws`	The live updates WebSocket

Database migrations are in crates/server/migrations/ and run on start. A monitor's settings are stored as JSON in one column, so new check types and channels don't need migrations.

How a check runs

A timer fires every second and finds active services whose next run is due.
For each, it schedules the next run and queues a check job in SQLite.
A worker runs the check with the service's timeout. Monitors in a maintenance window are skipped and logged as Maintenance.
The result is evaluated: failures count as Pending until the retries are used up, and invert swaps up and down.
The result is stored, and broadcast on /ws to open dashboards.
On a confirmed change (down, or back up), one alert job is queued per channel, and delivered with retries.

Frontend

frontend/ is SvelteKit with the static adapter, Tailwind and shadcn-svelte components. The server serves the built files from ASSETS_PATH and falls back to 404.html for client-side routes. The frontend talks to the server through /api and /ws.