Gemini Prediction Markets API

Schemas(1.0.0)

Error

error

string

Error code

Example: InvalidInput

message

string

Human-readable error message

Example: orderId is required

MarketStatus

string · enum

Enum values:

approved

active

closed

under_review

settled

invalid

Status of a prediction market

MarketType

string · enum

Enum values:

binary

categorical

Type of prediction market

OrderType

string · enum

Enum values:

limit

Order type (currently only limit orders are supported)

OrderSide

string · enum

Enum values:

buy

sell

Outcome

string · enum

Enum values:

yes

The outcome being traded (Yes or No)

TimeInForce

string · enum

Enum values:

good-til-cancel

immediate-or-cancel

fill-or-kill

maker-or-cancel

Order execution behavior:

good-til-cancel - Order remains active until filled or cancelled (default)
immediate-or-cancel - Fill immediately or cancel remaining
fill-or-kill - Fill entire order immediately or cancel
maker-or-cancel - Only add liquidity to the order book; if any part would fill immediately, the entire order is cancelled. Also known as "post-only".

Default: good-til-cancel

OrderStatus

string · enum

Enum values:

open

filled

cancelled

PositionStatus

string · enum

Enum values:

active

resolved

cancelled

Pagination

limit

integer

offset

integer

total

integer

PaginationSimple

limit

integer

offset

integer

count

integer

Number of items in current response

OrderBook

object[]

OrderBookEntry

side

string · enum

Enum values:

buy

sell

price

string

quantity

string

OrderBookDepth

object[]

lastUpdateTime

string · date-time

OrderBookLevel

price

string

quantity

string

orderCount

integer

Contract

id

string

label

string

Human-readable label (e.g., "Yes", "No")

abbreviatedName

string | null

Short form label (e.g., ">$90")

description

object

Rich text description

prices

object | null

Current bid/ask pricing for the contract

totalShares

string | null

color

string | null

status

string · enum

Status of a prediction market

Enum values:

approved

active

closed

under_review

settled

invalid

imageUrl

string | null

array | null

createdAt

string · date-time

expiryDate

string | null · date-time

resolutionSide

string · enum

The outcome being traded (Yes or No)

Enum values:

yes

resolvedAt

string | null · date-time

termsAndConditionsUrl

string

ticker

string

instrumentSymbol

string

effectiveDate

string | null · date-time

marketState

string | null · enum

Trading state of the contract

Enum values:

open

closed

sortOrder

integer | null

Display order within the event

object

Strike price information for Up/Down crypto contracts

source

string | null

Data source identifier for price observation (e.g., "GRR-KAIKO_BTCUSD_60S"). Present for crypto Up/Down contracts.

Example: GRR-KAIKO_BTCUSD_60S

settlementValue

string | null

The observed settlement price. Only present after the contract is settled.

Example: 87654.32

Strike

Strike price information for Up/Down crypto contracts

value

string | null

The strike price value. Null for "reference" type strikes where the value is determined at availableAt time.

Example: 87500.00

type

string · enum

Strike type - "reference" for Up/Down contracts, "above" for Higher/Lower contracts

Enum values:

reference

above

Example: reference

availableAt

string | null · date-time

When the strike price becomes available

Example: 2026-03-27T19:45:00.000Z

PricePoint

timestamp

string · date-time

price

string

ContractPrices

Event

A prediction market event containing one or more tradeable contracts

id

string

title

string

slug

string

description

string | null

imageUrl

string | null

type

string · enum

Type of prediction market

Enum values:

binary

categorical

category

string

series

string | null

ticker

string

The event ticker (e.g., "BTC100K2025")

Example: BTC100K2025

status

string · enum

Status of a prediction market

Enum values:

approved

active

closed

under_review

settled

invalid

resolvedAt

string | null · date-time

createdAt

string · date-time

object[]

Tradeable contracts within this event

object

volume

string

Total trading volume in USD

Example: 125000.00

liquidity

string

Total liquidity in USD

Example: 50000.00

tags

array | null

effectiveDate

string · date-time

expiryDate

string | null · date-time

subcategory

object | null

Nested category information for the event

source

string | null

Data source identifier for price observation. Aggregated from contracts for crypto Up/Down events.

Example: GRR-KAIKO_BTCUSD_60S

object

Settlement information for resolved events

Subcategory

Settlement

Settlement information for resolved events

value

string | null

The observed settlement value (e.g., the price at expiry for crypto contracts)

Example: 87654.32

EventsResponse

object[]

object

ContractMetadata

contractId

string

contractName

string

contractTicker

string

eventTicker

string

eventName

string

category

string

contractStatus

string

imageUrl

string | null

expiryDate

string | null · date-time

resolvedAt

string | null · date-time

description

string | null

OrderRequest

symbol

string · required

Contract instrument symbol

Example: GEMI-FEDJAN26-DN25

orderType

string · enum · required

Order type (currently only limit orders are supported)

Enum values:

limit

side

string · enum · required

Enum values:

buy

sell

quantity

string · required

Number of contracts

Example: 100

price

string · required

Limit price (0-1 range)

Example: 0.65

outcome

string · enum · required

The outcome being traded (Yes or No)

Enum values:

yes

timeInForce

string · enum

Order execution behavior:

good-til-cancel - Order remains active until filled or cancelled (default)
immediate-or-cancel - Fill immediately or cancel remaining
fill-or-kill - Fill entire order immediately or cancel
maker-or-cancel - Only add liquidity to the order book; if any part would fill immediately, the entire order is cancelled. Also known as "post-only".

Enum values:

good-til-cancel

immediate-or-cancel

fill-or-kill

maker-or-cancel

Default: good-til-cancel

OrderResponse

orderId

integer · int64

hashOrderId

string | null

clientOrderId

string | null

globalOrderId

string | null

status

string · enum

Enum values:

open

filled

cancelled

symbol

string

side

string · enum

Enum values:

buy

sell

outcome

string · enum

The outcome being traded (Yes or No)

Enum values:

yes

orderType

string · enum

Order type (currently only limit orders are supported)

Enum values:

limit

quantity

string

Original order quantity

filledQuantity

string

Amount filled so far

remainingQuantity

string

Amount remaining to fill

price

string

Limit price

avgExecutionPrice

string | null

Average price of fills

createdAt

string · date-time

updatedAt

string · date-time

cancelledAt

string | null · date-time

object

OrdersResponse

object[]

object

Position

symbol

string

instrumentId

integer · int64

totalQuantity

string

Total position size

avgPrice

string

Average entry price

outcome

string · enum

The outcome being traded (Yes or No)

Enum values:

yes

object

PositionsResponse

object[]

symbol

string

Contract instrument symbol

Example: GEMI-FED260318-CUT25

totalQty

string

Total taker volume across all participants (in shares)

Example: 94625

userAggressorQty

string | null

The authenticated user's taker (aggressor) volume (in shares)

Example: 1

userRestingQty

string | null

The authenticated user's maker (resting) volume (in shares)

Example: 0

VolumeMetricsResponse

eventTicker

string

The event ticker

Example: FED260318

object[]

TimeInForce

string · enum

Enum values:

good-til-cancel

immediate-or-cancel

fill-or-kill

maker-or-cancel

Order execution behavior:

good-til-cancel - Order remains active until filled or cancelled (default)
immediate-or-cancel - Fill immediately or cancel remaining
fill-or-kill - Fill entire order immediately or cancel
maker-or-cancel - Only add liquidity to the order book; if any part would fill immediately, the entire order is cancelled. Also known as "post-only".

Default: good-til-cancel

Contract

id

string

label

string

Human-readable label (e.g., "Yes", "No")

abbreviatedName

string | null

Short form label (e.g., ">$90")

description

object

Rich text description

prices

object | null

Current bid/ask pricing for the contract

totalShares

string | null

color

string | null

status

string · enum

Status of a prediction market

Enum values:

approved

active

closed

under_review

settled

invalid

imageUrl

string | null

array | null

createdAt

string · date-time

expiryDate

string | null · date-time

resolutionSide

string · enum

The outcome being traded (Yes or No)

Enum values:

yes

resolvedAt

string | null · date-time

termsAndConditionsUrl

string

ticker

string

instrumentSymbol

string

effectiveDate

string | null · date-time

marketState

string | null · enum

Trading state of the contract

Enum values:

open

closed

sortOrder

integer | null

Display order within the event

object

Strike price information for Up/Down crypto contracts

source

string | null

Data source identifier for price observation (e.g., "GRR-KAIKO_BTCUSD_60S"). Present for crypto Up/Down contracts.

Example: GRR-KAIKO_BTCUSD_60S

settlementValue

string | null

The observed settlement price. Only present after the contract is settled.

Example: 87654.32

Strike

Strike price information for Up/Down crypto contracts

value

string | null

The strike price value. Null for "reference" type strikes where the value is determined at availableAt time.

Example: 87500.00

type

string · enum

Strike type - "reference" for Up/Down contracts, "above" for Higher/Lower contracts

Enum values:

reference

above

Example: reference

availableAt

string | null · date-time

When the strike price becomes available

Example: 2026-03-27T19:45:00.000Z

Event

A prediction market event containing one or more tradeable contracts

id

string

title

string

slug

string

description

string | null

imageUrl

string | null

type

string · enum

Type of prediction market

Enum values:

binary

categorical

category

string

series

string | null

ticker

string

The event ticker (e.g., "BTC100K2025")

Example: BTC100K2025

status

string · enum

Status of a prediction market

Enum values:

approved

active

closed

under_review

settled

invalid

resolvedAt

string | null · date-time

createdAt

string · date-time

object[]

Tradeable contracts within this event

object

volume

string

Total trading volume in USD

Example: 125000.00

liquidity

string

Total liquidity in USD

Example: 50000.00

tags

array | null

effectiveDate

string · date-time

expiryDate

string | null · date-time

subcategory

object | null

Nested category information for the event

source

string | null

Data source identifier for price observation. Aggregated from contracts for crypto Up/Down events.

Example: GRR-KAIKO_BTCUSD_60S

object

Settlement information for resolved events

OrderRequest

symbol

string · required

Contract instrument symbol

Example: GEMI-FEDJAN26-DN25

orderType

string · enum · required

Order type (currently only limit orders are supported)

Enum values:

limit

side

string · enum · required

Enum values:

buy

sell

quantity

string · required

Number of contracts

Example: 100

price

string · required

Limit price (0-1 range)

Example: 0.65

outcome

string · enum · required

The outcome being traded (Yes or No)

Enum values:

yes

timeInForce

string · enum

Order execution behavior:

good-til-cancel - Order remains active until filled or cancelled (default)
immediate-or-cancel - Fill immediately or cancel remaining
fill-or-kill - Fill entire order immediately or cancel
maker-or-cancel - Only add liquidity to the order book; if any part would fill immediately, the entire order is cancelled. Also known as "post-only".

Enum values:

good-til-cancel

immediate-or-cancel

fill-or-kill

maker-or-cancel

Default: good-til-cancel

OrderResponse

orderId

integer · int64

hashOrderId

string | null

clientOrderId

string | null

globalOrderId

string | null

status

string · enum

Enum values:

open

filled

cancelled

symbol

string

side

string · enum

Enum values:

buy

sell

outcome

string · enum

The outcome being traded (Yes or No)

Enum values:

yes

orderType

string · enum

Order type (currently only limit orders are supported)

Enum values:

limit

quantity

string

Original order quantity

filledQuantity

string

Amount filled so far

remainingQuantity

string

Amount remaining to fill

price

string

Limit price

avgExecutionPrice

string | null

Average price of fills

createdAt

string · date-time

updatedAt

string · date-time

cancelledAt

string | null · date-time

object

ContractShareVolume

symbol

string

Contract instrument symbol

Example: GEMI-FED260318-CUT25

totalQty

string

Total taker volume across all participants (in shares)

Example: 94625

userAggressorQty

string | null

The authenticated user's taker (aggressor) volume (in shares)

Example: 1

userRestingQty

string | null

The authenticated user's maker (resting) volume (in shares)

Example: 0