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POST
/
exchange
Modify order
curl --request POST \
  --url https://api.hyperliquid.xyz/exchange \
  --header 'Content-Type: application/json' \
  --data '{
  "action": {
    "type": "modify",
    "oid": 123456789,
    "order": {
      "a": 0,
      "b": true,
      "p": "27.5",
      "s": "1.0",
      "r": false,
      "t": {
        "limit": {
          "tif": "Gtc"
        }
      },
      "c": "0x1234567890abcdef1234567890abcdef"
    }
  },
  "nonce": 1705234567890,
  "signature": {
    "r": "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
    "s": "0xfedcba0987654321fedcba0987654321fedcba0987654321fedcba0987654321",
    "v": 27
  },
  "vaultAddress": null
}'
{
  "status": "ok",
  "response": {
    "type": "modify",
    "data": {
      "statuses": [
        {
          "resting": {
            "oid": 77738309
          }
        }
      ]
    }
  }
}
This endpoint requires signature authentication. See our comprehensive Authentication via Signatures guide for implementation details.
Modifies an existing order on the Hyperliquid exchange. You can change the price, size, and other parameters without canceling and replacing the order.
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​
Parameters

​
Required parameters

  • action (object, required) — The modify action object containing:
    • type (string) — Must be "modify"
    • oid (number or string) — Order ID to modify, or cloid if using client order ID
    • order (object) — New order parameters:
      • a (number) — Asset index
      • b (boolean) — Is buy order (true for buy/long, false for sell/short)
      • p (string) — New limit price
      • s (string) — New size in units of the base asset
      • r (boolean) — Reduce only order
      • t (object) — Order type specification:
        • For limit orders: {"limit": {"tif": "Alo" | "Ioc" | "Gtc"}}
        • For trigger orders: {"trigger": {"isMarket": boolean, "triggerPx": string, "tpsl": "tp" | "sl"}}
      • c (string, optional) — New client order ID (128-bit hex string)
  • nonce (number, required) — Current timestamp in milliseconds (must be recent)
  • signature (object, required) — EIP-712 signature of the action

​
Optional parameters

  • vaultAddress (string, optional) — Address when trading on behalf of a vault or subaccount
  • expiresAfter (number, optional) — Timestamp in milliseconds after which the request is rejected

​
Returns

Returns an object with modification status:
  • status — "ok" if request processed
  • response — Contains modification details:
    • type — "modify"
    • data — Modification result information

​
Example request

curl -X POST https://api.hyperliquid.xyz/exchange \
  -H "Content-Type: application/json" \
  -d '{
    "action": {
      "type": "modify",
      "oid": 77738308,
      "order": {
        "a": 0,
        "b": true,
        "p": "51000",
        "s": "0.02",
        "r": false,
        "t": {"limit": {"tif": "Gtc"}}
      }
    },
    "nonce": 1234567890123,
    "signature": {...}
  }'

​
Modification behavior

  • Priority preservation — Modifying only the size preserves queue priority
  • Price changes — Changing the price moves the order to the back of the queue
  • Partial fills — Can modify partially filled orders (remaining size only)
  • Order types — Can change between different order types

​
Use cases

  • Price adjustment — Update limit price based on market movements
  • Size scaling — Increase or decrease order size
  • Strategy updates — Adjust orders without losing position in queue
  • Risk management — Convert orders to reduce-only
Modifying an order is more efficient than cancel-and-replace, especially when only changing the size, as it can preserve your position in the order queue.
Some modifications may cause loss of queue priority. Price changes always move the order to the back of the queue at the new price level.

Body

application/json
​
action
object
required
​
nonce
integer
required

Current timestamp in milliseconds

​
signature
object
required

EIP-712 signature of the action with r, s, v components

​
vaultAddress
string

Address when trading on behalf of a vault or subaccount (optional)

​
expiresAfter
integer

Timestamp in milliseconds after which the request is rejected (optional)

Response

200 - application/json

Order modification result

​
status
string

Request status

​
response
object
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