Modify order | Hyperliquid exchange

Modifies an existing order on the Hyperliquid exchange. You can change the price, size, and other parameters without canceling and replacing the order.

POST /exchange

Modify order

cURL

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
}
'

200

{
  "status": "ok",
  "response": {
    "type": "modify",
    "data": {
      "statuses": [
        {
          "resting": {
            "oid": 77738309
          }
        }
      ]
    }
  }
}

You can only use this endpoint on the official Hyperliquid public API. It is not available through Chainstack, as the open-source node implementation does not support it yet. See Hyperliquid methods for the full availability breakdown.

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

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

Show child attributes

nonce · integer · required

Current timestamp in milliseconds

signature · object · required

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

Show child attributes

vaultAddress · string | null

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

Show child attributes