Dashdown Docs

Real-time data

A :::query block opts into live streaming with the live attribute: interval=N sets the poll cadence in seconds (default 5, floored to 1). The component opens a WebSocket to /_dashdown/ws/data/{query} and repaints whenever the result changes — no page reload, no extra wiring.

The demos below use DuckDB's random() / now() so the result changes on every poll and the updates are visible offline — watch them tick. A real dashboard would point a live query at a table that actually mutates (order counts, error rates, queue depth).

Tip

Streaming is additive: a query without live behaves exactly as before. And in a dashdown build static export live is a no-op — the page falls back to the one-shot snapshot, so these examples still render (just frozen) with no server.

Live KPI #

A counter that re-reads its query every 2 seconds.

Downloads (live)

Live chart #

Downloads by channel, re-sampled every 2 seconds.

Live table #

A "recent activity" feed — five daily rows re-shuffled every 3 seconds.

Pointing live at real data #

Nothing about the component changes for genuinely live sources — only the query. Because a live query re-runs on every poll, a query that reads an external endpoint re-fetches it each tick. DuckDB (which backs the csv/duckdb connectors) can read a remote JSON API directly, so no new connector is needed:

:::query name=btc_price connector=main live interval=5
SELECT CAST(data.amount AS DOUBLE) AS usd
FROM read_json_auto('https://api.coinbase.com/v2/prices/BTC-USD/spot')
:::

<Counter data={btc_price} column="usd" format="currency" decimals=2 label="BTC / USD (live)" />

If a poll fails (rate limit, network blip) the server retries on the next tick and the component keeps showing its last good value — live queries are self-healing, so an occasional upstream hiccup isn't fatal.

Note

Live streaming needs a running server, so it pairs with auth: none (browsers can't send Basic/api-key credentials on a WebSocket handshake). See the framework README's "Real-time" section for the fan-out and caching details.

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