> ## Documentation Index > Fetch the complete documentation index at: https://docs.qfex.com/llms.txt > Use this file to discover all available pages before exploring further. # Order Entry — Modify Order Orders can be modified over **WebSocket**.\ Only **`price`**, **`quantity`**, **`take_profit`**, and **`stop_loss`** may be changed. * You **must** specify the order’s **`order_id`** (UUID v4). * You **must** specify the **`symbol`**. * You **must** specify the **`side`**. * You **must** specify the **`order_type`**. * `client_order_id` cannot be used for modifies. ## 1) Authenticate Send this immediately after you connect: ```json theme={null} { "type": "auth", "params": { "hmac": { "public_key": "qfex_pub_xxxxx", "nonce": "c0ffee...", "unix_ts": 1760545414, "signature": "5f2e..." } } } ``` ## 2) Modify Order ```json theme={null} { "type": "modify_order", "params": { "order_id": "510333ac-3f7b-4d88-934a-4396d48824cc", "symbol": "AAPL-USD", "side": "BUY", "quantity": 2, "price": 200, "take_profit": 200, "stop_loss": 150 } } ``` ## Parameters | Field | Type | Required | Description | | ------------- | ------ | -------- | -------------------------------------------------------------------------------------------------- | | `order_id` | string | ✅ | UUID v4 of the order to modify. | | `symbol` | string | ✅ | The market symbol (e.g. `AAPL-USD`). | | `side` | enum | ✅ | Must match the original order’s side. See [OrderDirection](/api-reference/enums#orderdirection). | | `order_type` | enum | ✅ | Must match the original order’s type. See [OrderType](/api-reference/enums#OrderType). | | `quantity` | number | Optional | New order quantity. Must respect symbol lot size, min, and max constraints. | | `price` | number | Optional | New price for limit/ALO orders. Ignored for market orders. Must respect tick size and price bands. | | `take_profit` | number | Optional | Updated take-profit price. Set `0` if unused. | | `stop_loss` | number | Optional | Updated stop-loss price. Set `0` if unused. | > ⚠️ Notes: > > * Only `price`, `quantity`, `take_profit`, and `stop_loss` may be modified. > * `client_order_id` cannot be used for modifies. > * **The `order_id` changes on modification.** The response will contain a **new** `order_id`. The old `order_id` is replaced. This is because multiple in-flight amends are not currently supported. > * Modifications that would cause an invalid state (e.g. reducing below partially filled quantity) will be rejected with [OrderStatus](/api-reference/enums#orderstatus) codes such as `CANNOT_MODIFY_PARTIAL_FILL` or `CANNOT_MODIFY_NO_SUCH_ORDER`. ## Sample Code ```python python theme={null} # Python (websocket-client) import json, websocket API_KEY = "YOUR_API_KEY" def send(ws, obj): ws.send(json.dumps(obj)) def on_open(ws): # Authenticate # https://docs.qfex.com/websocket/channels/trade/authenticate#how-it-works send(ws, {"type": "auth", "params": { "hmac": { "public_key": "qfex_pub_xxxxx", "nonce": "c0ffee...", "unix_ts": 1760545414, "signature": "5f2e..." }}}) # Modify order send(ws, { "type": "modify_order", "params": { "order_id": "510333ac-3f7b-4d88-934a-4396d48824cc", "symbol": "AAPL-USD", "side": "BUY", "order_type": "LIMIT", "quantity": 2, "price": 200, "take_profit": 200, "stop_loss": 150 } }) ws = websocket.WebSocketApp( "wss://trade.qfex.com?api_key=YOUR_API_KEY", on_open=on_open, on_message=lambda _, m: print("Message:", m) ) ws.run_forever() ``` ```javascript node theme={null} // Node.js (ws) import WebSocket from "ws"; const ws = new WebSocket("wss://trade.qfex.com?api_key=YOUR_API_KEY"); const API_KEY = "YOUR_API_KEY"; ws.on("open", () => { // Authenticate ws.send(JSON.stringify({ type: "auth", params: { api_key: API_KEY } })); // Modify order ws.send( JSON.stringify({ type: "modify_order", params: { order_id: "510333ac-3f7b-4d88-934a-4396d48824cc", symbol: "AAPL-USD", side: "BUY", order_type: "LIMIT", quantity: 2, price: 200, take_profit: 200, stop_loss: 150, }, }) ); }); ws.on("message", (msg) => console.log("Message:", msg.toString())); ``` ```go go theme={null} // Go (gorilla/websocket) package main import ( "log" "github.com/gorilla/websocket" ) func mustWriteJSON(c *websocket.Conn, v any) { if err := c.WriteJSON(v); err != nil { log.Fatal("write:", err) } } func main() { c, _, err := websocket.DefaultDialer.Dial("wss://trade.qfex.com?api_key=YOUR_API_KEY", nil) if err != nil { log.Fatal("dial:", err) } defer c.Close() // Authenticate mustWriteJSON(c, map[string]any{ "type": "auth", "params": map[string]any{"hmac": map[string]any{"public_key": "qfex_pub_xxxxx", "nonce": "c0ffee...", "unix_ts": 1760545414, "signature": "5f2e..."}} }) // Modify order mustWriteJSON(c, map[string]any{ "type": "modify_order", "params": map[string]any{ "order_id": "510333ac-3f7b-4d88-934a-4396d48824cc", "symbol": "AAPL-USD", "side": "BUY", "order_type": "LIMIT", "quantity": 2, "price": 200, "take_profit": 200, "stop_loss": 150, }, }) } ``` ```java java theme={null} // Java (OkHttp WebSocket) import java.util.concurrent.TimeUnit; import okhttp3.*; public class ModifyOrderWs { public static void main(String[] args) { OkHttpClient client = new OkHttpClient.Builder() .pingInterval(20, TimeUnit.SECONDS).build(); Request req = new Request.Builder() .url("wss://trade.qfex.com?api_key=YOUR_API_KEY").build(); WebSocketListener li = new WebSocketListener() { @Override public void onOpen(WebSocket ws, Response r) { // Authenticate ws.send("{\"type\": \"auth\", \"params\": { \"hmac\": { \"public_key\": \"qfex_pub_xxxxx\", \"nonce\": \"c0ffee...\..\", \"unix_ts\": 1760545414, \"signature\": \"5f2e...\" }}}"); // Modify order ws.send("{\"type\":\"modify_order\",\"params\":{\"order_id\":\"510333ac-3f7b-4d88-934a-4396d48824cc\",\"symbol\":\"AAPL-USD\",\"side\":\"BUY\",\"order_type\":\"LIMIT\",\"original_quantity\":1,\"quantity\":2,\"price\":200,\"take_profit\":200,\"stop_loss\":150}}"); } @Override public void onMessage(WebSocket ws, String text) { System.out.println(text); } }; client.newWebSocket(req, li); try { Thread.sleep(Long.MAX_VALUE); } catch (InterruptedException ignored) {} } } ``` ## Example Response When an order is successfully modified, you receive the same `order_response` object as with add, but with status **`MODIFIED`** and a **new** `order_id` (the old one is replaced). ```json theme={null} { "order_response": { "order_id": "88888888-4444-4444-4444-1234567890ab", "symbol": "AAPL-USD", "status": "MODIFIED", "quantity": 2.0, "price": 200.0, "take_profit": 200.0, "stop_loss": 150.0, "side": "BUY", "type": "LIMIT", "time_in_force": "GTC", "user_id": "0020ce8e-eaee-480e-8d7f-b9241d756ee5", "client_order_id": "", "quantity_remaining": 2.0, "trade_id": null } } ```