SimpleFunctions Developer Manual

Use the Real-Time Data API when you need raw market data for a terminal, dashboard, bot, or trading agent. This surface is separate from simplefunctions.dev/api/public/*. The public API is for analytical objects and agent workflows. The data API is for fast market data. Last verified: 2026-05-06.

Base URLs

REST:

https://data.simplefunctions.dev/v1

Current public WebSocket:

wss://app.simplefunctions.dev/ws

Do not use wss://data.simplefunctions.dev/v1/ws yet. It is the intended canonical data-domain WebSocket name, but current routing can return 426 Upgrade Required. Use wss://app.simplefunctions.dev/ws until the WS route is moved off Vercel or a direct WS CNAME is configured.

Data conventions

Field	Convention
Prices	Probabilities in `[0, 1]`, not cents.
`generated_at`	Unix seconds.
`closeTime`	Unix seconds.
`ts`	Unix milliseconds.
Compression	Large REST responses are gzip-compressed by the origin.

Coverage and hydration

The data API is backed by an in-memory market registry plus venue REST fallbacks.

Path	Coverage behavior
Browse endpoints such as `/v1/markets`, `/v1/snapshot`, `/v1/movers`, and broad `/v1/search`	Use the warm registry and recent in-memory samples. They are fast and intentionally bounded.
Exact Kalshi ticker reads such as `/v1/markets/{ticker}`, `/v1/orderbook/{ticker}`, `/v1/candles/{ticker}`, and exact ticker search	Attempt direct Kalshi hydration when the ticker missed the warm registry.
Trades	Return recent in-memory trade prints. Empty trades means no recent cached prints, not necessarily no historical volume.

Hydration is exact-ticker only. It is not a general text-search crawler.

REST endpoints

Endpoint	Use	Cache
`GET /v1/heartbeat`	Health/status payload.	`max-age=10`
`GET /v1/markets?q=&venue=`	Top tracked markets or registry search.	`max-age=3`
`GET /v1/markets/featured?n=50`	Heat-ranked featured markets.	`max-age=3`
`GET /v1/markets/{ticker}`	One market snapshot.	`max-age=2`
`GET /v1/search?q=&limit=&venue=&strict=`	Autocomplete-grade ticker/title search.	`max-age=5`
`GET /v1/snapshot`	Compact full active-universe price snapshot.	`max-age=2`
`GET /v1/movers?window=&n=&minVol=&dir=`	Top price movers over a recent window.	`max-age=5`
`GET /v1/orderbook/{ticker}`	Top-of-book/depth snapshot.	`max-age=1`
`GET /v1/candles/{ticker}?tf=1h&limit=500`	OHLCV candles.	`max-age=5` or `15` for `1d`
`GET /v1/trades/{ticker}?limit=50`	Recent trade prints.	`max-age=1`

Heartbeat

curl "https://data.simplefunctions.dev/v1/heartbeat"

{
  "markets_tracked": 9333,
  "ws_clients": 3,
  "top_volume_market": "KXPRESNOMD-28-GN",
  "uptime_s": 12345,
  "generated_at": 1777553300
}

Markets

curl "https://data.simplefunctions.dev/v1/markets"
curl "https://data.simplefunctions.dev/v1/markets?q=newsom&venue=kalshi"
curl "https://data.simplefunctions.dev/v1/markets?q=KXHORMUZWEEKLY-26MAY10-T40"
curl "https://data.simplefunctions.dev/v1/markets/featured?n=50"
curl "https://data.simplefunctions.dev/v1/markets/KXPRESNOMD-28-GN"

Market object:

{
  "ticker": "KXPRESNOMD-28-GN",
  "venue": "kalshi",
  "title": "Will Gavin Newsom be the Democratic Presidential nominee in 2028?",
  "lastPrice": 0.26,
  "volume24h": 12345,
  "closeTime": 1853884800,
  "bestBid": 0.25,
  "bestAsk": 0.27,
  "heat": 81.4
}

Search

curl "https://data.simplefunctions.dev/v1/search?q=newsom&limit=10"
curl "https://data.simplefunctions.dev/v1/search?q=rate%20cut&venue=kalshi&strict=0"
curl "https://data.simplefunctions.dev/v1/search?q=KXHORMUZWEEKLY-26MAY10-T40&strict=0"

Parameters:

Parameter	Values	Use
`q`	string	Required query.
`limit`	`1` to `50`	Result cap. Default `10`.
`venue`	`kalshi`, `polymarket`	Optional venue filter.
`strict`	`1`, `0`	`strict=0` enables looser substring matching for short tokens.

Response:

{
  "query": "newsom",
  "results": [
    {
      "ticker": "KXPRESNOMD-28-GN",
      "venue": "kalshi",
      "title": "Will Gavin Newsom be the Democratic Presidential nominee in 2028?",
      "lastPrice": 0.26,
      "volume24h": 12345,
      "score": 400
    }
  ]
}

Raw snapshot

curl "https://data.simplefunctions.dev/v1/snapshot"

Use this for bot cold-start. It intentionally omits title, close time, and heat to keep the payload small. Markets pinned outside [0.01, 0.99] are excluded.

{
  "generated_at": 1777553300,
  "count": 9000,
  "markets": [
    {
      "ticker": "KXPRESNOMD-28-GN",
      "venue": "kalshi",
      "last": 0.26,
      "bid": 0.25,
      "ask": 0.27,
      "vol24h": 12345
    }
  ]
}

Movers

curl "https://data.simplefunctions.dev/v1/movers?window=1h&n=50&minVol=1000&dir=both"

Parameters:

Parameter	Values	Use
`window`	`1m`, `5m`, `15m`, `1h`, `4h`, `24h`, `1d`	Move window. Default `1h`.
`n`	`10` to `200`	Result cap. Default `50`.
`minVol`	number	24h volume floor. Default `1000`.
`dir`	`up`, `down`, `both`	Direction filter. Default `both`.

/v1/movers is powered by in-memory tick/trade samples. After deploy or reconnect, short windows can return count: 0 until samples accumulate.

Orderbook, candles, trades

curl "https://data.simplefunctions.dev/v1/orderbook/KXPRESNOMD-28-GN"
curl "https://data.simplefunctions.dev/v1/candles/KXPRESNOMD-28-GN?tf=1h&limit=500"
curl "https://data.simplefunctions.dev/v1/trades/KXPRESNOMD-28-GN?limit=50"

For valid Kalshi tickers that are not already in the warm registry, the market, orderbook, and candle paths attempt direct venue hydration before returning the current cache view. Orderbook:

{
  "ticker": "KXPRESNOMD-28-GN",
  "bids": [[0.25, 1200]],
  "asks": [[0.27, 700]],
  "ts": 1777553300123
}

Candles:

{
  "ticker": "KXPRESNOMD-28-GN",
  "timeframe": "1h",
  "candles": [
    { "t": 1777550400000, "o": 0.25, "h": 0.27, "l": 0.24, "c": 0.26, "v": 900 }
  ]
}

Trades:

{
  "ticker": "KXPRESNOMD-28-GN",
  "trades": [
    {
      "ticker": "KXPRESNOMD-28-GN",
      "venue": "kalshi",
      "price": 0.26,
      "size": 10,
      "side": "buy",
      "ts": 1777553300123
    }
  ]
}

WebSocket

const ws = new WebSocket('wss://app.simplefunctions.dev/ws')

ws.addEventListener('open', () => {
  ws.send(JSON.stringify({
    action: 'subscribe',
    topics: [
      'featured',
      'ticker:KXPRESNOMD-28-GN',
      'orderbook:KXPRESNOMD-28-GN',
      'trade:KXPRESNOMD-28-GN',
      'candle:KXPRESNOMD-28-GN:1m'
    ],
  }))
})

ws.addEventListener('message', (event) => {
  const frame = JSON.parse(event.data)
  console.log(frame.type, frame)
})

Subscribe:

{
  "action": "subscribe",
  "topics": [
    "featured",
    "ticker:KXPRESNOMD-28-GN",
    "orderbook:KXPRESNOMD-28-GN",
    "trade:KXPRESNOMD-28-GN",
    "candle:KXPRESNOMD-28-GN:1m"
  ]
}

Unsubscribe:

{
  "action": "unsubscribe",
  "topics": ["ticker:KXPRESNOMD-28-GN"]
}

Legacy single-topic subscribe is also accepted:

{ "action": "subscribe", "ticker": "KXPRESNOMD-28-GN" }

WebSocket topics

Topic	Frame type	Use
`featured`	`featured`	Top-50 heat-ranked list.
`ticker:{ticker}`	`ticker_info`	Latest price/quote metadata.
`orderbook:{ticker}`	`orderbook`	Sorted book snapshot.
`trade:{ticker}`	`trade`	Trade prints from venue WS.
`candle:{ticker}:{tf}`	`candle`	Candle updates for one timeframe.
`{ticker}`	mixed	Legacy topic with ticker/orderbook/trade/candle fan-out.

When subscribing to a ticker topic, the server may send initial cached ticker_info and orderbook frames if available.

Frame shapes

featured:

{
  "type": "featured",
  "markets": [],
  "generated_at": 1777553300
}

ticker_info:

{
  "type": "ticker_info",
  "ticker": "KXPRESNOMD-28-GN",
  "venue": "kalshi",
  "title": "Will Gavin Newsom be the Democratic Presidential nominee in 2028?",
  "last": 0.26,
  "bid": 0.25,
  "ask": 0.27,
  "volume24h": 12345,
  "closeTime": 1853884800
}

orderbook, trade, and candle use the same shapes as the REST examples above, with a top-level type.

Operational notes

Public REST callers use https://data.simplefunctions.dev/v1; the edge proxy injects the internal origin token.
Direct origin routes at https://app.simplefunctions.dev/api/data/v1/* are edge-token gated and return 403 without the internal token.
Anonymous WebSocket connections are capped per IP.
The server pings WebSocket clients every 30 seconds and closes stale connections after a failed pong.
Kalshi and Polymarket are normalized into one ticker namespace, but not all fields are available from both venues.
A non-empty market response and an empty trades response can both be healthy: trades are process-local recent prints, while market metadata can be hydrated from venue REST.

​Base URLs

​Data conventions

​Coverage and hydration

​REST endpoints

​Heartbeat

​Markets

​Search

​Raw snapshot

​Movers

​Orderbook, candles, trades

​WebSocket

​WebSocket topics

​Frame shapes

​Operational notes