> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt
> Use this file to discover all available pages before exploring further.

# evmUserModify | Hyperliquid exchange

> Modifies user settings from the HyperEVM side. Allows EVM-based accounts to update their Hyperliquid L1 configuration. On Hyperliquid exchange.

<Info>
  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](/docs/hyperliquid-methods) for the full availability breakdown.
</Info>

<Note>
  This endpoint requires signature authentication. See our comprehensive [Authentication via Signatures guide](/docs/hyperliquid-authentication-guide) for implementation details.
</Note>

Modifies user settings from the HyperEVM side. Allows EVM-based accounts to update their Hyperliquid L1 configuration.

## Parameters

### Required parameters

* `action` (object, required) — The action object containing:
  * `type` (string) — Must be `"evmUserModify"`
  * `modifications` (array) — Array of modification objects
* `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

## Returns

Returns an object with the action status:

* `status` — `"ok"` if request processed
* `response` — Contains action result data

## Example request

<CodeGroup>
  ```shell cURL theme={"system"}
  curl -X POST https://api.hyperliquid.xyz/exchange \
    -H "Content-Type: application/json" \
    -d '{
      "action": {"type": "evmUserModify"},
      "nonce": 1234567890123,
      "signature": {...}
    }'
  ```

  ```python Python (hyperliquid-python-sdk) theme={"system"}
  import eth_account
  from hyperliquid.exchange import Exchange
  from hyperliquid.utils import constants

  # Load the wallet that signs the action.
  wallet = eth_account.Account.from_key("YOUR_PRIVATE_KEY")

  # evmUserModify is public-only, so use the Hyperliquid mainnet API.
  exchange = Exchange(wallet, constants.MAINNET_API_URL)

  # Configure the block type for HyperEVM transactions.
  result = exchange.use_big_blocks(True)
  print(result)
  ```

  ```typescript TypeScript (@nktkas/hyperliquid) theme={"system"}
  import { ExchangeClient, HttpTransport } from "@nktkas/hyperliquid";
  import { privateKeyToAccount } from "viem/accounts";

  // Load the wallet that signs the action.
  const wallet = privateKeyToAccount("0x...");

  // evmUserModify is public-only, so use the default Hyperliquid transport.
  const transport = new HttpTransport();
  const client = new ExchangeClient({ transport, wallet });

  // Configure the block type for HyperEVM transactions.
  const result = await client.evmUserModify({ usingBigBlocks: true });
  console.log(result);
  ```
</CodeGroup>

## Use case

* **EVM user modify** — Modifies user settings from the HyperEVM side. Allows EVM-based accounts to update their Hyperliquid L1 configuration.

<Warning>
  Always ensure your system clock is synchronized. Nonce must be within a reasonable time window of the current server time or the request will be rejected.
</Warning>


## OpenAPI

````yaml openapi/hyperliquid_node_api/hypercore_exchange/exchange_evm_user_modify.json post /exchange
openapi: 3.0.0
info:
  title: Hyperliquid Exchange API
  version: 1.0.0
  description: >-
    API for trading operations on Hyperliquid exchange. **IMPORTANT**: All
    exchange endpoints require EIP-712 signatures for authentication. The
    examples shown will not work without proper signing. See the [Hyperliquid
    Python SDK](https://github.com/hyperliquid-dex/hyperliquid-python-sdk) for
    implementation examples.
servers:
  - url: https://api.hyperliquid.xyz
security: []
paths:
  /exchange:
    post:
      tags:
        - hyperliquid exchange
      summary: EVM user modify
      operationId: evmUserModify
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                action:
                  type: object
                  properties:
                    type:
                      type: string
                      default: evmUserModify
                      enum:
                        - evmUserModify
                      description: Action type
                    usingBigBlocks:
                      type: boolean
                      description: >-
                        Whether to enable big block mode for HyperEVM
                        transactions
                  required:
                    - type
                    - usingBigBlocks
                nonce:
                  type: integer
                  description: Current timestamp in milliseconds
                signature:
                  type: object
                  description: EIP-712 signature of the action with r, s, v components
                  properties:
                    r:
                      type: string
                      description: ECDSA signature r component (hex string)
                      example: >-
                        0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef
                    s:
                      type: string
                      description: ECDSA signature s component (hex string)
                      example: >-
                        0xfedcba0987654321fedcba0987654321fedcba0987654321fedcba0987654321
                    v:
                      type: integer
                      description: ECDSA recovery id (27 or 28)
                      example: 27
                  required:
                    - r
                    - s
                    - v
                vaultAddress:
                  type: string
                  description: >-
                    Address when trading on behalf of a vault or subaccount
                    (optional)
                  nullable: true
              required:
                - action
                - nonce
                - signature
            example:
              action:
                type: evmUserModify
                usingBigBlocks: true
              nonce: 1705234567890
              signature:
                r: >-
                  0x0000000000000000000000000000000000000000000000000000000000000000
                s: >-
                  0x0000000000000000000000000000000000000000000000000000000000000000
                v: 27
              vaultAddress: null
      responses:
        '200':
          description: Action result
          content:
            application/json:
              schema:
                type: object
                properties:
                  status:
                    type: string
                    description: Request status
                  response:
                    type: object
                    description: Action response data

````