Place Order

REST APIs Prediction Markets Order ManagementPlace Order

Place Order

POSThttps://api.gemini.com/v1/prediction-markets/order

Place a prediction market limit or stop-limit order. For active trading and market making, prefer WebSocket order.place; use REST order placement for payload reference and one-off server workflows. For post-only/maker-only REST behavior, set makerOrCancel to true.

POSTv1/prediction-markets/order

curl --request POST \
  --url https://api.gemini.com/v1/prediction-markets/order \
  --header 'Content-Type: application/json' \
  --header 'X-GEMINI-APIKEY: <string>' \
  --header 'X-GEMINI-PAYLOAD: <string>' \
  --header 'X-GEMINI-SIGNATURE: <string>' \
  --data '
{
  "symbol": "GEMI-FEDJAN26-DN25",
  "orderType": "limit",
  "side": "buy",
  "quantity": "100",
  "price": "0.65",
  "outcome": "yes",
  "timeInForce": "good-til-cancel"
}
'

Terms

Before sending a Prediction Markets order, check Get Terms Status. If the latest terms are not accepted, display Get Terms and call Accept Terms, then retry the order.

Roles

The API key you use to access this endpoint must have the Trader role assigned. See Roles for more information.

The OAuth scope must have orders:create assigned to access this endpoint. See OAuth Scopes for more information.

REST vs WebSocket Payloads

WebSocket is the preferred path for active trading and market making. REST order placement is for reference and one-off server workflows. REST and WebSocket order payloads are not interchangeable:

Task	WebSocket Code `order.place`	REST Code `POST /v1/prediction-markets/order`
Outcome	Code `eventOutcome: "YES"`	Code `outcome: "yes"`
Order type	Code `type: "LIMIT"`	Code `orderType: "limit"`
Maker-only	Code `timeInForce: "MOC"`	Code `timeInForce: "good-til-cancel"` , Code `makerOrCancel: true`
Side	Code `side: "BUY"`	Code `side: "buy"`

Headers

X-GEMINI-APIKEYstring·required

Your API key

X-GEMINI-SIGNATUREstring·required

HEX-encoded HMAC-SHA384 of payload signed with API secret

X-GEMINI-PAYLOADstring·required

Base64-encoded JSON payload

Content-Typestring

Default: text/plain

Content-Lengthstring

Default: 0

Cache-Controlstring

Default: no-cache

Request Body

symbolstring·required

Contract instrument symbolExample: GEMI-FEDJAN26-DN25

orderTypestring·enum·required

Order type. `stop-limit` orders require a `stopPrice` that triggers a limit order at `price` when the market reaches the trigger.Enum values: limitstop-limit

sidestring·enum·required

Enum values: buysell

quantitystring·required

Number of contractsExample: 100

pricestring·required

Limit price (0-1 range)Example: 0.65

stopPricestring

The price to trigger a stop-limit order (0-1 range). Only available for stop-limit orders. See [Stop-Limit Orders](#operation/placeOrder) above for `stopPrice`/`price` constraints.Example: 0.60

outcomestring·enum·required

The outcome being traded (Yes or No)Enum values: yesno

timeInForcestring·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 cancelEnum values: good-til-cancelimmediate-or-cancelfill-or-kill

makerOrCancelboolean

Set to `true` to require maker-only behavior. If the order would immediately take liquidity, the order is cancelled instead of filling.

Responses

Order created successfully

orderIdinteger (int64)

Example: 12345678

hashOrderIdstring

clientOrderIdstring

globalOrderIdstring

statusstring·enum

Enum values: openfilledcancelled

symbolstring

sidestring·enum

Enum values: buysell

outcomestring·enum

The outcome being traded (Yes or No)Enum values: yesno

orderTypestring·enum

Order type. `stop-limit` orders require a `stopPrice` that triggers a limit order at `price` when the market reaches the trigger.Enum values: limitstop-limit

quantitystring

Original order quantity

filledQuantitystring

Amount filled so far

remainingQuantitystring

Amount remaining to fill

pricestring

Limit price

stopPricestring

Stop trigger price (populated for `stop-limit` orders)

avgExecutionPricestring

Average price of fills

createdAtstring (date-time)

updatedAtstring (date-time)

cancelledAtstring (date-time)

contractMetadataobject

contractMetadata.contractIdstring

contractMetadata.contractNamestring

contractMetadata.contractTickerstring

contractMetadata.eventTickerstring

contractMetadata.eventNamestring

contractMetadata.categorystring

contractMetadata.contractStatusstring

contractMetadata.eventTypestring

Event type ("binary" or "categorical")

contractMetadata.expiryDatestring (date-time)

contractMetadata.resolvedAtstring (date-time)

contractMetadata.resolutionSidestring

Winning outcome if resolved ("yes" or "no")

contractMetadata.parentEventTickerstring

Parent event ticker for sub-events

contractMetadata.startTimestring (date-time)

Start datetime (ISO 8601)

PreviousOrder Management NextCancel Order

Last modified on June 17, 2026

curl --request POST \ --url https://api.gemini.com/v1/prediction-markets/order \ --header 'Content-Type: application/json' \ --header 'X-GEMINI-APIKEY: <string>' \ --header 'X-GEMINI-PAYLOAD: <string>' \ --header 'X-GEMINI-SIGNATURE: <string>' \ --data ' { "symbol": "GEMI-FEDJAN26-DN25", "orderType": "limit", "side": "buy", "quantity": "100", "price": "0.65", "outcome": "yes", "timeInForce": "good-til-cancel" } '

REST vs WebSocket Payloads

WebSocket is the preferred path for active trading and market making. REST order placement is for reference and one-off server workflows. REST and WebSocket order payloads are not interchangeable:

Task	WebSocket Code `order.place`	REST Code `POST /v1/prediction-markets/order`
Outcome	Code `eventOutcome: "YES"`	Code `outcome: "yes"`
Order type	Code `type: "LIMIT"`	Code `orderType: "limit"`
Maker-only	Code `timeInForce: "MOC"`	Code `timeInForce: "good-til-cancel"` , Code `makerOrCancel: true`
Side	Code `side: "BUY"`	Code `side: "buy"`

Request Body

symbolstring·required

Contract instrument symbolExample: GEMI-FEDJAN26-DN25

orderTypestring·enum·required

Order type. `stop-limit` orders require a `stopPrice` that triggers a limit order at `price` when the market reaches the trigger.Enum values: limitstop-limit

sidestring·enum·required

Enum values: buysell

quantitystring·required

Number of contractsExample: 100

pricestring·required

Limit price (0-1 range)Example: 0.65

stopPricestring

The price to trigger a stop-limit order (0-1 range). Only available for stop-limit orders. See [Stop-Limit Orders](#operation/placeOrder) above for `stopPrice`/`price` constraints.Example: 0.60

outcomestring·enum·required

The outcome being traded (Yes or No)Enum values: yesno

timeInForcestring·enum

makerOrCancelboolean

Set to `true` to require maker-only behavior. If the order would immediately take liquidity, the order is cancelled instead of filling.

Responses

Order created successfully

orderIdinteger (int64)

Example: 12345678

hashOrderIdstring

clientOrderIdstring

globalOrderIdstring

statusstring·enum

Enum values: openfilledcancelled

symbolstring

sidestring·enum

Enum values: buysell

outcomestring·enum

The outcome being traded (Yes or No)Enum values: yesno

orderTypestring·enum

Order type. `stop-limit` orders require a `stopPrice` that triggers a limit order at `price` when the market reaches the trigger.Enum values: limitstop-limit

quantitystring

Original order quantity

filledQuantitystring

Amount filled so far

remainingQuantitystring

Amount remaining to fill

pricestring

Limit price

stopPricestring

Stop trigger price (populated for `stop-limit` orders)

avgExecutionPricestring

Average price of fills

createdAtstring (date-time)

updatedAtstring (date-time)

cancelledAtstring (date-time)

contractMetadataobject

contractMetadata.contractIdstring

contractMetadata.contractNamestring

contractMetadata.contractTickerstring

contractMetadata.eventTickerstring

contractMetadata.eventNamestring

contractMetadata.categorystring

contractMetadata.contractStatusstring

contractMetadata.eventTypestring

Event type ("binary" or "categorical")

contractMetadata.expiryDatestring (date-time)

contractMetadata.resolvedAtstring (date-time)

contractMetadata.resolutionSidestring

Winning outcome if resolved ("yes" or "no")

contractMetadata.parentEventTickerstring

Parent event ticker for sub-events

contractMetadata.startTimestring (date-time)

Start datetime (ISO 8601)