---
title: "Simulate an order before signing"
method: GET
path: "/v1/order-preflight"
---

# Simulate an order before signing

`GET /v1/order-preflight`

## Request

- Base URL: `https://api.epsilon.exchange`
- URL: `https://api.epsilon.exchange/v1/order-preflight`
- Auth: API key in header `X-API-Key`

Checks balances, allowances, route viability, and fee-leg consistency for an order as it would be signed.

## Query parameters

- `tokenIn` string, required
- `tokenOut` string, required
- `amountIn` string, required
- `wallet` string, required
- `slippagePpm` integer
- `isStopLoss` '0' | '1'

## Response `200`

Preflight result

- object

## Other responses

- `401`: Missing or invalid API key
- `429`: Per-key rate limit exceeded — see X-RateLimit-* and Retry-After headers

---

[API](https://skmtc.dev/epsilon/apis/epsilon-public-api.md) · [All operations](https://skmtc.dev/epsilon/apis/epsilon-public-api/llms.txt) · [OpenAPI document](https://skmtc.dev/epsilon/apis/epsilon-public-api/revisions/8a6e06ae2b0d?raw)