Starbase Reference Data and Instrument Definitions

Instrument metadata for the Starbase Binary API, including InstrumentDefinition fields, index and mark price sources, and quantityExponent snapshot behavior.

Reference data

Combination Orders: Combination orders are treated as orders on outright books and are not differentiated in any way. Their orderbook_id links to a combination order book.

Multicast is the recommended source for full reference data. The Starbase REST API exposes a subset of instrument fields and does not include all attributes available in the SBE InstrumentDefinition message — for example, combination legs, large tick size steps, and the instrument flags are not available via REST. Use the multicast reference data feed to obtain complete instrument definitions.

Reference data sources

The Starbase and standard Deribit APIs expose overlapping, but not identical, instrument metadata:

Source	Access	Use it for
SBE multicast InstrumentDefinition	Starbase private connectivity	Authoritative Starbase order-entry units, minimum quantity, tick sizes, instrument type, status, and combo legs
Standard public/get_instruments	Standard public JSON-RPC API; Starbase network access is not required	Standard instrument metadata including contract_size, index_id, and product_group
Starbase REST get_instruments	Starbase private connectivity	index_id, product_group, qty_tick_size, and a subset of standard instrument metadata; fields such as contract_size may be absent or null
FIX SecurityList	Standard FIX session	FIX contract-based metadata including ContractMultiplier

Do not assume that a field available through one interface is available through every other interface. In particular, use the multicast InstrumentDefinition when constructing or validating SBE order-entry messages.

Index prices and derived statistics

Index prices, mark prices, price bands, funding, and open interest are published on the multicast feeds via three dedicated messages:

Message	Contents	Update frequency
IndexInfo (12)	Index price per currency pair, shared across the pair’s instruments	On index price change
InstrumentInfo (14)	Price band (minSellPrice/maxBuyPrice) and mark price per instrument	Frequently
InstrumentRef (15)	Funding, settlement/delivery prices, and open interest per instrument	Less frequently

On the snapshot channel, every cycle starts with IndexInfo messages — one for each known index price on the channel, batched into as few packets as fit — so snapshot joiners receive current index prices before the per-instrument sequences.

These values are also available from the standard Deribit API:

Data	Sources
Index price	deribit_price_index.{index_name} WebSocket channel, public/get_index_price, or ticker.{instrument}.{interval}
Mark price, funding, open interest	ticker.{instrument}.{interval} WebSocket channel, public/ticker, or public/get_book_summary_by_instrument

Quantity units and contract size

Starbase does not use contract counts or contract size for matching. All SBE order, quote, trade, and position quantities use Deribit’s native amount:

quantityAsset	Starbase amount unit
USD	Dollar value
The instrument’s base currency, such as BTC or ETH	Number of coins

Encode amounts directly as Decimal72, determine whether the amount represents dollar value or coins from quantityAsset, and validate the value against minOrderQuantity.

Do not derive a contract count before sending an SBE quantity, and do not copy a FIX OrderQty expressed in contracts into an SBE message. contract_size and FIX ContractMultiplier remain available for standard JSON-RPC and FIX workflows, but Starbase does not consume either value.

Starbase is designed as a closed system for latency-sensitive matching. Broker, clearing, and other account-management workflows remain on the standard Deribit APIs, so applications that use those workflows may still need the standard reference data in addition to the Starbase feed.

InstrumentDefinition (10)

Field	Name	Type	Length	Description
1	instrumentId	int64	8	Numeric instrument ID
2	name	char	128	Name of instrument on Deribit
3	indexId	int64	8	The associated index
4	underlying	char	64	The underlying future; only applicable to options
5	quantityAsset	char	8	Asset used for quantity/amount
6	priceAsset	char	8	Asset used for pricing
7	expiryTime	int64	8	Nanoseconds since epoch. Time of expiration (optional)
8	strikePrice	int64	8	Strike price mantissa (×10⁻⁹); optional
9	minOrderQuantity	int64	8	Minimum order quantity mantissa (aka baseIncrement); resolved value = minOrderQuantity × 10^quantityExponent
10	tickSize	int64	8	Default tick size mantissa (×10⁻⁹)
11	quantityExponent	int8	1	Exponent applied to all quantity fields (value = mantissa × 10^quantityExponent)
12	type	int8	1	0=PerpFuture 1=Option 2=Spot 3=FutureCombo 4=OptionCombo 5=DatedFuture
13	flags	uint8	1	Instrument attributes (see flags table below)
14	status	int8	1	0=Open 1=Inactive 2=Settlement 3=Delivered 4=Locked 5=Halted
15	blockLengthOfLargeTickSizes	uint16	2	Block length of each largeTickSizes group entry
16	numberOfLargeTickSizes	uint16	2	Number of large tick size steps
->17	largeTickSize	int64	8	Tick size mantissa (×10⁻⁹) applicable when price ≥ thresholdPrice
->18	thresholdPrice	int64	8	Prices at or above this value use largeTickSize
19	blockLengthOfLegs	uint16	2	Block length of each legs group entry
20	numberOfLegs	uint16	2	Number of legs in the combination instrument. Maximum 4
->21	legInstrumentId	int64	8	Numeric instrumentId of the leg instrument
->22	ratio	int8	1	Amount of leg traded per combination unit. Positive = buy leg when buying combo

The table below outlines the content of field 13 (flags) of InstrumentDefinition.

Bit (0 = LSB)	Name	Description
0	isReversed	Set if the instrument is inverse
1	isPutOption	Set if the option is a put
2	isPerpetual	Set if the instrument is perpetual

quantityExponent (field 11) is available via the multicast snapshot only — no API returns it as a field of its own. It derives from the instrument’s quantity tick size: a tick of 1 maps to 0, 0.1 to -1, 0.01 to -2, and so on.

Quantity tick size across SBE and REST

The Starbase REST get_instruments endpoint and the standard public/get_instruments method both return qty_tick_size, which carries the same information as the SBE quantityExponent but as a single decimal rather than a mantissa and an exponent: qty_tick_size = minOrderQuantity × 10^quantityExponent.

Reading the equivalent value from SBE therefore requires both minOrderQuantity (field 9) and quantityExponent (field 11), not quantityExponent alone:

REST	SBE	Value
qty_tick_size = 1	minOrderQuantity = 1, quantityExponent = 0	1
qty_tick_size = 0.1	minOrderQuantity = 1, quantityExponent = -1	1 × 10⁻¹ = 0.1
qty_tick_size = 0.01	minOrderQuantity = 1, quantityExponent = -2	1 × 10⁻² = 0.01

The two representations are guaranteed to resolve to the same value for a given instrument.

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IndexDefinition (11)

Sent at the start of the snapshot cycle, followed by IndexInfo.

Field	Name	Type	Length	Description
1	indexId	int64	8	Currency pair ID
2	name	char	128	Name of index

IndexInfo (12)

Sent when an index price changes, and at the start of every snapshot cycle (one per known index price on the channel, batched into as few packets as fit). The index price is per currency pair and is shared across the pair’s instruments.

Field	Name	Type	Length	Description
1	indexId	int64	8	Currency pair ID
2	indexPrice	int64	8	Index price mantissa (×10⁻⁹)

InstrumentInfo (14)

Frequently updated per-instrument fields.

Field	Name	Type	Length	Description
1	instrumentId	int64	8	Numeric instrument ID
2	minSellPrice	int64	8	Lower price band: minimum sell price mantissa (×10⁻⁹)
3	maxBuyPrice	int64	8	Upper price band: maximum buy price mantissa (×10⁻⁹)
4	markPrice	int64	8	Mark price mantissa (×10⁻⁹)

InstrumentRef (15)

Less frequently updated per-instrument fields. All value fields are optional — a field carries its null value when not applicable to the instrument (for example, funding fields on dated futures).

Field	Name	Type	Length	Description
1	instrumentId	int64	8	Numeric instrument ID
2	currentFunding	double	8	Current funding rate (optional)
3	funding8h	double	8	8-hour funding rate (optional)
4	estimatedDeliveryPrice	int64	8	Estimated delivery price mantissa (×10⁻⁹); optional
5	deliveryPrice	int64	8	Delivery price mantissa (×10⁻⁹); optional
6	settlementPrice	int64	8	Settlement price mantissa (×10⁻⁹); optional
7	openInterest	double	8	Open interest (optional)

InstrumentStatusUpdate (16)

Field	Name	Type	Length	Description
1	instrumentId	int64	8	Numeric instrument ID
2	tradingStatus	int8	1	0=Open 1=Inactive 2=Settlement 3=Delivered 4=Locked 5=Halted