# `Bourse.Ticker`
[🔗](https://github.com/ZenHive/bourse/blob/main/lib/bourse/ticker.ex#L1)

Unified market ticker data.

Contains the latest price, volume, and spread information for a trading pair.

## Fields

  * `symbol` - Unified symbol (e.g., "BTC/USDT")
  * `timestamp` - Exchange timestamp in milliseconds
  * `datetime` - ISO 8601 datetime string
  * `high`, `low` - 24h high/low prices
  * `bid`, `bid_volume` - Best bid price and volume
  * `ask`, `ask_volume` - Best ask price and volume
  * `vwap` - Volume-weighted average **price** (or `nil` when the venue does not
    supply volume units that form a price — see caveats below)
  * `open`, `close`, `last` - 24h open, close, and last trade prices
  * `previous_close` - Previous 24h close
  * `change`, `percentage` - 24h absolute change and percentage in percent points (10 = 10%)
  * `average` - Average of open and close
  * `base_volume`, `quote_volume` - 24h volume in base/quote currency
  * `index_price`, `mark_price` - Derivatives index/mark prices
  * `info` - Raw exchange response

## `vwap` caveat (carve C36)

`vwap` is a **price**. It is only populated when the venue's volume operands
are quote-notional over base-quantity (or the venue publishes a weighted
average price directly). Blind `quoteVolume / baseVolume` is **not** always a
price: on OKX SWAP/FUTURES, `vol24h` is contracts and `volCcy24h` is base
currency, so that ratio collapses to contract size (`ctVal`, e.g. `0.01` on
BTC-USDT-SWAP) rather than a ~mark price. We diverge from Bourse's
always-divide carve there and leave `vwap` nil; consumers needing contract
volume should read `base_volume` / `quote_volume` / raw `info`. See
`docs/authored-specs.md` carve **C36**.

# `t`

```elixir
@type t() :: %Bourse.Ticker{
  ask: number() | nil,
  ask_volume: number() | nil,
  average: number() | nil,
  base_volume: number() | nil,
  bid: number() | nil,
  bid_volume: number() | nil,
  change: number() | nil,
  close: number() | nil,
  datetime: String.t() | nil,
  high: number() | nil,
  index_price: number() | nil,
  info: map() | nil,
  last: number() | nil,
  low: number() | nil,
  mark_price: number() | nil,
  open: number() | nil,
  percentage: number() | nil,
  previous_close: number() | nil,
  quote_volume: number() | nil,
  symbol: String.t() | nil,
  timestamp: integer() | nil,
  vwap: number() | nil
}
```

# `schema`

```elixir
@spec schema() :: map()
```

JSON Schema for the Ticker unified type.

---

*Consult [api-reference.md](api-reference.md) for complete listing*