> For the complete documentation index, see [llms.txt](https://docs.nexus.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nexus.xyz/api-reference/trading/edit-order-v1.md).

# PATCH /api/v1/orders/{order\_id}

Amend an order.

`operationId`: `editOrderV1` · CCXT method: `editOrder` · Rate-limit class: `trading`

**Authentication:** `hmacAuth`.

Atomic cancel-replace amend of a resting order: changes the price and/or size in a single operation. At least one of `price` or `size` must be supplied. Liquidation orders are not amendable, and a pre-trade margin check is applied to the projected replacement before it is accepted. That check excludes the reservation still held by the order being replaced, so an amend is sized on the margin the replacement actually adds rather than on the original and the replacement together: repricing a resting order at the same size needs no additional margin, and shrinking one frees margin rather than requiring it.

An amend does not restart execution. The replacement carries the original's `filled_qty` forward, so `quantity` stays the total you asked for and an order can never execute more than that total, across any number of amends: a Buy 5 that has filled 2 has 3 left to execute both before and after a reprice, and the replacement comes back as `PartiallyFilled` rather than `Open`. `size` sets the new TOTAL quantity, fills included, and must be greater than `filled_qty` — a size at or below it is rejected with InvalidAmend; cancel the order instead.

## Parameters

| Name        | In    | Type     | Required | Description                                       |
| ----------- | ----- | -------- | -------- | ------------------------------------------------- |
| `order_id`  | path  | `string` | Yes      | —                                                 |
| `market_id` | query | `string` | Yes      | Market the order rests on (required for routing). |

## Request body

**Required.** [`AmendOrderRequest`](/api-reference/guides/schemas.md#amendorderrequest) — `application/json`.

```json
{
  "price": "50100",
  "size": "0.2"
}
```

## Responses

| Status | Body                                              | Meaning                                                                                                                                                                                                                                                                                                                                                                                              |
| ------ | ------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `200`  | [`Order`](/api-reference/guides/schemas.md#order) | Amended order (the replacement, with a fresh id).                                                                                                                                                                                                                                                                                                                                                    |
| `400`  | — *(no schema declared)*                          | Invalid amend (empty body, invalid price/size, order not amendable, or margin breach)                                                                                                                                                                                                                                                                                                                |
| `401`  | — *(no schema declared)*                          | —                                                                                                                                                                                                                                                                                                                                                                                                    |
| `403`  | — *(no schema declared)*                          | —                                                                                                                                                                                                                                                                                                                                                                                                    |
| `404`  | — *(no schema declared)*                          | Order not found                                                                                                                                                                                                                                                                                                                                                                                      |
| `409`  | — *(no schema declared)*                          | The market-lifecycle admission gate, evaluated on the replacement before the original is touched: `MarketHalted` when the market is halted, `MarketReduceOnly` when the market is in reduce-only and the replacement is neither `reduce_only` nor a liquidation, and `MarketSuspended` when the market is settling or delisted. Rejected atomically — the original order is left resting, untouched. |
| `429`  | — *(no schema declared)*                          | —                                                                                                                                                                                                                                                                                                                                                                                                    |

## Example

```bash
curl -X PATCH 'https://exchange.nexus.xyz/api/exchange/api/v1/orders/{order_id}' \
  -H 'X-API-Key: nx_7f3a1b...' \
  -H 'X-Timestamp: 1776033911836' \
  -H 'X-Signature: <hmac-sha256>' \
  -H 'Content-Type: application/json'
```

***

<sub>Generated from</sub> <sub></sub><sub>`eng/apps/exchange/api/openapi.json`</sub> <sub></sub><sub>(spec</sub> <sub></sub><sub>`0.9.27`</sub><sub>). Do not edit by hand — regenerate with</sub> <sub></sub><sub>`python3 product/docs/tools/api-reference/generate.py`</sub><sub>. Hand-authored context lives in the Guides pages.</sub>


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