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

# TradeIncremental

> Market data schema, template 3

<div className="api-banner">
  <span className="api-protocol ws">SBE</span>
  <span className="api-detail">schema 34 · market data</span>
  <span className="api-tag">template 3</span>
</div>

One trade on an instrument.

**Direction:** Kraken → client

| ID | Field | Type | Encoding | Presence | Description |
| :- | :- | :- | :- | :- | :- |
| 1 | `instrumentId` | [`InstrumentId`](/exchange/api-reference/sbe/market-data-types#instrumentid) | field | required | |
| 2 | `transactTime` | [`TimestampNs`](/exchange/api-reference/sbe/market-data-types#timestampns) | field | required | Time the trade occurred at the source |
| 4 | `tradeSeq` | `uint64` | field | required | Contiguous per-instrument trade sequence, starting at one |
| 5 | `tradeId` | [`TradeId`](/exchange/api-reference/sbe/market-data-types#tradeid) | field | required | |
| 6 | `orderId` | [`OrderId`](/exchange/api-reference/sbe/market-data-types#orderid) | field | required | Aggressor order ID for this trade |
| 7 | `price` | [`Price`](/exchange/api-reference/sbe/market-data-types#price) | field | required | |
| 8 | `quantity` | [`Quantity`](/exchange/api-reference/sbe/market-data-types#quantity) | field | required | |
| 9 | `aggressorSide` | [`AggressorSide`](/exchange/api-reference/sbe/market-data-types#aggressorside) | field | optional | |
| 10 | `ordType` | [`OrdTypeMD`](/exchange/api-reference/sbe/market-data-types#ordtypemd) | field | optional | |

Every message is preceded by the standard SBE `messageHeader` (`blockLength`, `templateId`, `schemaId`, `version`). See [encodings](/exchange/api-reference/sbe/market-data-types#messageheader).