POST /api/v1/orders/preview

Preview an order

Preview an order.

operationId: previewOrderV1 · Rate-limit class: trading

Declared server differs from the callable one. This path declares its own servers base of https://exchange.nexus.xyz, without the /api/exchange mount the document default carries. Measured 2026-09-02, the override is not routed — https://exchange.nexus.xyz/api/v1/orders/preview returns 404 while the gateway form in the sample below is routed. A client generated from this contract will aim at the override; pin the gateway base until the per-network hosts are live. See Networks.

Not reachable through CCXT. Pre-trade simulation. CCXT has no unified preview/dry-run method.

Authentication: hmacAuth.

Pre-trade preview: projects the margin/equity/fee impact of an order without submitting it.

Request body

Required. OrderRequest — application/json.

Responses

Status	Body	Meaning
200	PreviewResponse	Projected pre-trade impact.
400	— (no schema declared)	Validation error
401	— (no schema declared)	—
429	— (no schema declared)	—

Example

cURL

curl -X POST 'https://exchange.nexus.xyz/api/exchange/api/v1/orders/preview' \
  -H 'X-API-Key: nx_7f3a1b...' \
  -H 'X-Timestamp: 1776033911836' \
  -H 'X-Signature: <hmac-sha256>' \
  -H 'Content-Type: application/json'

Python

import requests

headers = {
    "X-API-Key": "nx_7f3a1b...",
    "X-Timestamp": "1776033911836",
    "X-Signature": "<hmac-sha256>",
    "Content-Type": "application/json"
}

response = requests.post("https://exchange.nexus.xyz/api/exchange/api/v1/orders/preview", headers=headers)
response.raise_for_status()
print(response.json())

TypeScript

const response = await fetch("https://exchange.nexus.xyz/api/exchange/api/v1/orders/preview", {
  method: "POST",
  headers: {
    "X-API-Key": "nx_7f3a1b...",
    "X-Timestamp": "1776033911836",
    "X-Signature": "<hmac-sha256>",
    "Content-Type": "application/json"
  },
});
if (!response.ok) throw new Error(`${response.status} ${await response.text()}`);
console.log(await response.json());

X-Signature is a placeholder: it is derived from this specific request. See Authentication for the canonical string and the HMAC rule.

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_{Generated from eng/apps/exchange/api/openapi.json (spec 0.9.36). Do not edit by hand — regenerate with python3 product/docs/tools/api-reference/generate.py. Hand-authored context lives in the Guides pages.}