> ## Documentation Index
> Fetch the complete documentation index at: https://docs.struct.to/llms.txt
> Use this file to discover all available pages before exploring further.

# Asset Price Window Update

> Get notified when a crypto asset candle opens or closes.

<Note>
  **Event:** `asset_price_window_update` \
  **Endpoint:** `wss://api.struct.to/ws/alerts` \
  **Cost:** 0.1 credits per event
</Note>

Get notified when a crypto asset candle opens or closes. Use filters to narrow alerts to specific symbols or timeframes.

<Tip>
  **Related guide:** [Crypto Up/Down feed](/guides/crypto-up-down-feed) builds on these window open and close events to resolve Up/Down outcomes.
</Tip>

## Filters

| Filter          | Type      | Required | Description                                                                    |
| --------------- | --------- | -------- | ------------------------------------------------------------------------------ |
| `asset_symbols` | string\[] | No       | Supported symbols: `BTC`, `ETH`, `SOL`, `XRP`, `DOGE`, `BNB`, `HYPE` (max 500) |
| `timeframes`    | string\[] | No       | Valid timeframes: `5m`, `15m`, `1h`, `4h`, `1d`, `24h` (max 500)               |

<Note>The backend normalizes `1d` to `24h` in the response `variant` field.</Note>

## Subscribe

```json theme={null}
{
  "op": "subscribe",
  "event": "asset_price_window_update",
  "asset_symbols": ["BTC", "ETH"],
  "timeframes": ["1h", "4h"]
}
```

## Response

```json theme={null}
{
  "event": "asset_price_window_update",
  "timestamp": 1775913505260,
  "data": {
    "symbol": "BTC",
    "variant": "1h",
    "start_time": 1775910000000,
    "end_time": 1775913600000,
    "open_price": 84120.50,
    "close_price": 84532.17,
    "update_type": "close"
  }
}
```