# estimateExternalTransfer

Pre-deposit estimate for a swap-public-style external transfer.

Models the full pipeline: entry bridge (source → shielding chain) → Curvy fee
on the shielded amount → exit bridge (shielding chain → destination). Returns
the projected delivered amount plus a per-leg fee breakdown. Either leg can
be skipped (returns 0) when the corresponding chain/currency matches the
shielding side.

Uses the same LiFi bridge allowlist as the backend broadcaster, so the actual
route Curvy picks server-side should differ by at most a few bps from this
estimate.

## Import

```ts
import { estimateExternalTransfer } from "@0xcurvy/curvy-sdk/actions";
```

## Usage

```ts
const estimate = await estimateExternalTransfer({ fromNetwork, fromCurrency, fromAmount, toNetwork, toCurrency });
```

## Signature

```ts
function estimateExternalTransfer(parameters: EstimateExternalTransferParameters): Promise<EstimateExternalTransferResult>
```

## Returns

`Promise<EstimateExternalTransferResult>`

The action resolves or returns the value shown in the signature.

## Parameters

### `fromNetwork`

- **Type:** `Network`
- **Required:** yes

The public network from which funds enter the transfer.

```ts
const result = await estimateExternalTransfer({
  fromNetwork, // [!code focus]
  fromCurrency,
  fromAmount,
  toNetwork,
  toCurrency,
});
```

### `fromCurrency`

- **Type:** `Currency`
- **Required:** yes

The source currency.

```ts
const result = await estimateExternalTransfer({
  fromNetwork,
  fromCurrency, // [!code focus]
  fromAmount,
  toNetwork,
  toCurrency,
});
```

### `fromAmount`

- **Type:** `bigint`
- **Required:** yes

The gross source amount in the source currency's base units.

```ts
const result = await estimateExternalTransfer({
  fromNetwork,
  fromCurrency,
  fromAmount, // [!code focus]
  toNetwork,
  toCurrency,
});
```

### `toNetwork`

- **Type:** `Network`
- **Required:** yes

The public network on which the recipient receives funds.

```ts
const result = await estimateExternalTransfer({
  fromNetwork,
  fromCurrency,
  fromAmount,
  toNetwork, // [!code focus]
  toCurrency,
});
```

### `toCurrency`

- **Type:** `Currency`
- **Required:** yes

The currency the recipient receives.

```ts
const result = await estimateExternalTransfer({
  fromNetwork,
  fromCurrency,
  fromAmount,
  toNetwork,
  toCurrency, // [!code focus]
});
```

### `shieldingNetworkSlug`

- **Type:** `string`
- **Required:** no

Which aggregator network to shield on, by slug. Defaults to the source chain
when it has its own aggregator (no entry bridge — mirrors the deposit rule),
otherwise the first active aggregator network. Multi-aggregator deployments
should pass this (or the planner will, once value-tiered routing lands).

```ts
const result = await estimateExternalTransfer({
  fromNetwork,
  fromCurrency,
  fromAmount,
  toNetwork,
  toCurrency,
  shieldingNetworkSlug, // [!code focus]
});
```

### `config`

- **Type:** `CurvyConfig`
- **Required:** no

Curvy config to use. Defaults to the ambient config.

```ts
const result = await estimateExternalTransfer({
  fromNetwork,
  fromCurrency,
  fromAmount,
  toNetwork,
  toCurrency,
  config, // [!code focus]
});
```

## Errors

Errors from config resolution and the underlying SDK operation are propagated to the caller.

## Related

- [Interacting with assets guide](/for-programmers/interacting-with-assets)
- [`estimateIntent`](/sdk/actions/planner/estimateIntent) — Select spendable notes and return fees, delivered amount, a sanitized route, and an in-memory handle that can be passed to executeIntent.
- [`executeIntent`](/sdk/actions/planner/executeIntent) — Execute a handle returned by estimateIntent.
- [`getPlanSteps`](/sdk/actions/planner/getPlanSteps) — Return the ordered, sanitized steps an integrator can present to a user.
- [`estimateBridge`](/sdk/actions/bridge/estimateBridge) — Quote a bridge/swap before committing — for the swap UI (in-app/public) and send-with-exit-bridge.

## Source

[packages/@0xcurvy/sdk/src/actions/planner/estimateExternalTransfer.ts](https://github.com/0xCurvy/curvy-monorepo/blob/main/packages/@0xcurvy/sdk/src/actions/planner/estimateExternalTransfer.ts)