| Name | Type | Description | Notes |
|---|---|---|---|
| from | Array<PreviewFromParam> | Sell side; each item is the currency + the swap amount `amount` (string decimal). | [default to undefined] |
| to | Array<PreviewToParam> | Target side; each item is currency + ratio `ratio` (string decimal, such as `0.5`). Typical source: `GET /asset-swap/config` → `recommend_v2` `schemes[].name` / `schemes[].ratio` of the strategy under a certain group. | [default to undefined] |