Market Data Incremental Refresh

Incremental order book and trade updates via FIX

FIXsession: market-data35=X

Incremental updates to the order book and trades following a Market Data Snapshot Full Refresh.

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header · required

35=X

262 - MDReqID · string · required

Unique request identifier.

55 - Symbol · string · required

Asset Pair listed on the exchange.

268 - NoMDEntries · integer · required

Number of entries following. If several entries are present they need to be parsed in order (for example creation and deletion of an entry in the book can happen in the same message).

Hide repeating group

279 - MDUpdateAction · integer · required

Always first field in this repeating group.

Possible values:

• 0 : New — Creation of an entry in the book
• 1 : Update — Update of a quantity for an entry in the book
• 2 : Delete — Deletion of an entry in the book

269 - MDEntryType · integer · required

Possible values:

• 0 : Bid
• 1 : Offer
• 2 : Trade

278 - MDEntryID · string · required

Unique identifier for this market data entry. Corresponding to the OrderID for Level 3 subscription.

270 - MDEntryPx · float · required

Price of the market data entry.

271 - MDEntrySize · float · required

Volume represented by the market data entry.

273 - MDEntryTime · string · required

The time the entry was inserted or amended or deleted.

5060 - MDEntryTimestamp · string

High-precision event time for this market data update. Level 3 only. When present with 5273, 5060 is the time the update was generated; 5273 is the queue entry time. Sample format: 2026-02-03T10:24:34.650069468Z (ISO 8601, nanosecond fractional seconds, UTC).

5273 - MDEntryTimeQueue · string

Queue entry time: when the order entered the book at this price level. Level 3 only. For L3, orders at the same price are ordered by this tag. Sample format: 2026-02-03T10:24:29.175114502Z (ISO 8601, nanosecond fractional seconds, UTC).

40 - OrdType · char

The order type of the taker order.

Possible values:

• 1 : market
• 2 : Limit

Condition: MDEntryType = Trade

2446 - AggressorSide · char

The side of the taker order.

Possible values:

• 1 : Buy
• 2 : Sell

Condition: MDEntryType = Trade

5041 - ChecksumOrderBook · string

Checksum to verify the orderbook update. See Checksum article.

Condition: MDEntryType = Bid or Offer

trailer · required

Spot L2 Example

8=FIX.4.4|9=213|35=X|34=100|56=MYCOMPID|49=KRAKEN-MD|52=20230707-13:42:27.230|55=BTC/USD|262=1|268=2|279=2|269=1|278=O30300.7|270=30300.7|271=0.0|273=13:42:27.208|279=0|269=1|278=O31941.0|270=31941.0|271=0.0031746|273=20:40:00.455|10=112|