Playground
Utility(3 methods)
conninfoGet the connection rate limits.
pingPing the server to check connectivity.
timeGet the current server time in milliseconds since Unix epoch.
Subscriptions(3 methods)
SUBSCRIBESubscribe to public data streams such as {symbol}@bookTicker. Account streams such as orders@account, balances@account, and positions@account require an authenticated WebSocket handshake outside the browser playground.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| params | array | required | Array of stream names to subscribe to |
UNSUBSCRIBEUnsubscribe from data streams.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| params | array | required | Array of stream names to unsubscribe from |
LIST_SUBSCRIPTIONSGet a list of all active stream subscriptions for the current connection.
L2 Data(1 method)
depthGet a snapshot of the order book depth for a prediction market symbol. Use [price, quantity] levels to compute notional dollars locally.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| symbol | string | required | Prediction market symbol (e.g., GEMI-BTC05M2606011000-UP) |
| limit | number | optional | Number of price levels to return (max: 5000)(default: 100) |
Trading(4 methods)
order.placeAuth RequiredPlace a new prediction market order. Requires authentication outside the browser playground. For a first quote, use LIMIT with MOC so the order rests or cancels instead of taking liquidity.
Browser WebSocket connections cannot send Gemini authentication headers during the upgrade. Copy this request into a non-browser client or use a server-side proxy for authenticated streams and trading methods.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| symbol | string | required | Prediction market symbol (e.g., GEMI-BTC05M2606011000-UP) |
| side | string | required | Order side: BUY or SELL |
| type | string | required | Order type: LIMIT or MARKET. Use LIMIT with MOC time in force for maker-only quotes. |
| timeInForce | string | required | Time in force: GTC (Good Till Cancel), IOC (Immediate or Cancel), FOK (Fill or Kill), MOC (Maker or Cancel). MOC cancels instead of taking liquidity. |
| price | string | optional | Order price between 0.01 and 0.99 (required for LIMIT orders) |
| quantity | string | required | Number of contracts |
| eventOutcome | string | required | YES (predicting the event happens) or NO (predicting it doesn't) |
| clientOrderId | string | optional | Client-provided order ID for tracking |
order.cancelAuth RequiredCancel an existing order by order ID.
Browser WebSocket connections cannot send Gemini authentication headers during the upgrade. Copy this request into a non-browser client or use a server-side proxy for authenticated streams and trading methods.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| orderId | string | required | Order ID to cancel (from the i field in order events) |
order.cancel_allAuth RequiredCancel all existing orders.
Browser WebSocket connections cannot send Gemini authentication headers during the upgrade. Copy this request into a non-browser client or use a server-side proxy for authenticated streams and trading methods.
order.cancel_sessionAuth RequiredCancel all existing orders for the current session.
Browser WebSocket connections cannot send Gemini authentication headers during the upgrade. Copy this request into a non-browser client or use a server-side proxy for authenticated streams and trading methods.