> For the complete documentation index, see [llms.txt](https://hinkal-team.gitbook.io/hinkal/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hinkal-team.gitbook.io/hinkal/hinkal-mobile-sdk/android/guides/swaps.md).

# Swaps

A private swap trades one token for another entirely inside the private balance, with no public trace of the trade. It runs server-side through a Hinkal relayer.

### Quote first

Get a quote before swapping. Use `getEvmSwapPrices` on EVM chains, `getSolanaSwapPrices` on Solana:

```kotlin
val quoteJson = hinkal.getEvmSwapPrices(chainId, inWei, inToken, outToken)
```

The quote returns the swap data you pass into `swap`.

### Basic Swap

```kotlin
val txHash = hinkal.swap(
    chainId,
    "[\"$inToken\", \"$outToken\"]",
    "[\"$inWei\"]",
    actionID,
    swapData,
    inToken,   // feeToken
    "",        // feeStructureJSON
)
```

On Solana use `swapSolana(...)`, which omits `actionID`:

```kotlin
val txHash = hinkal.swapSolana(
    chainId,
    "[\"$inToken\", \"$outToken\"]",
    "[\"$inWei\"]",
    swapData,
    outToken,   // feeToken
    "",         // feeStructureJSON
)
```

### Parameters

<table data-search="false"><thead><tr><th>Parameter</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td><code>chainID</code></td><td><code>Long</code></td><td>Target chain id.</td></tr><tr><td><code>tokenAddrsJSON</code></td><td><code>String</code></td><td>JSON array: input token, then output token.</td></tr><tr><td><code>amountsWeiJSON</code></td><td><code>String</code></td><td>JSON array with the input amount in wei.</td></tr><tr><td><code>actionID</code></td><td><code>String</code></td><td>DEX action id from the quote (EVM only).</td></tr><tr><td><code>swapData</code></td><td><code>String</code></td><td>Encoded swap data from the quote.</td></tr><tr><td><code>feeToken</code></td><td><code>String</code></td><td>Token the fee is paid in.</td></tr><tr><td><code>feeStructureJSON</code></td><td><code>String</code></td><td>Fee quote, or empty for defaults.</td></tr></tbody></table>

### Error Handling

```kotlin
try {
    val txHash = hinkal.swap(chainId, "[\"$inToken\", \"$outToken\"]", "[\"$inWei\"]",
                             actionID, swapData, inToken, "")
} catch (e: Exception) {
    Log.e("Hinkal", "Swap failed: ${e.message}")
}
```

### Best Practices

#### 1. Always quote immediately before swapping

Quotes move. Fetch a fresh quote with `getEvmSwapPrices` / `getSolanaSwapPrices` right before calling `swap`, and pass its `swapData` unchanged.

```kotlin
val quote = hinkal.getEvmSwapPrices(chainId, inWei, inToken, outToken)
```

#### 2. Use the right method per chain

Use `swap` on EVM/Tron (it takes `actionID`) and `swapSolana` on Solana (no `actionID`). Branch on `Mobile.isSolanaChain(chainId)`.

#### 3. Refresh the balance afterward

```kotlin
hinkal.getTotalBalance(chainId, signature, address, true, false)
```