<!--
Sitemap:
- [Interop SDK Documentation](/index): Build multichain TypeScript apps with interoperable addresses, cross-chain quotes, transfer execution, and order tracking across providers.
- [Install Interop SDK](/installation): Install @wonderland/interop-addresses and @wonderland/interop-cross-chain, then choose the package that fits your multichain app.
- [Addresses Module](/addresses/): Parse, encode, and resolve chain-aware addresses that combine an account, chain, and optional ENS name into one unambiguous identifier.
- [Addresses: Getting Started](/addresses/getting-started): Parse an interoperable address and extract its components — go from a human-readable name like vitalik.eth@eip155:1 to address and chain ID.
- [Addresses: Concepts](/addresses/concepts): How EIP-7930, ERC-7828, and CAIP-350 combine address and chain into a single, unambiguous, validated identifier for multichain apps.
- [Parsing an Interoperable Name](/addresses/example): Walkthrough for wallet developers — extract the raw address and chain ID from an interop address so legacy contracts keep working.
- [Addresses: Advanced Usage](/addresses/advanced-usage): Advanced patterns for interoperable addresses — checksums, validation, error handling, and round-trip conversions between formats.
- [Addresses: API Reference](/addresses/api): Function signatures and types for the interop-addresses package — high-level helpers, name-layer methods, and binary-layer primitives.
- [Cross-Chain Module](/cross-chain/): One open source integration for cross-chain actions — compare quotes across providers, execute orders, and track completion.
- [Cross-Chain: Getting Started](/cross-chain/getting-started): Execute a cross-chain token transfer end-to-end — create a provider, fetch a quote, send the transaction, and track the order to completion.
- [Cross-Chain: Concepts](/cross-chain/concepts): The intent-based architecture behind the cross-chain package and how the SDK unifies heterogeneous bridge providers behind a common interface.
- [Supported Providers](/cross-chain/providers): Supported cross-chain providers (Across, Relay, OIF, Bungee, LiFi Intents) and how to configure each via createCrossChainProvider.
- [Across Provider](/cross-chain/across-provider): Configure and use the Across Protocol provider for cross-chain token transfers via the Across bridge infrastructure.
- [Relay Provider](/cross-chain/relay-provider): Configure and use the Relay Protocol provider for cross-chain transfers, including opt-in gasless execution via EIP-3009 signatures.
- [OIF Provider](/cross-chain/oif-provider): Direct integration with any OIF-compliant solver — submission modes, resource locks, and configuration for Open Intents Framework backends.
- [Bungee Provider](/cross-chain/bungee-provider): Cross-chain token transfers via Bungee — onchain transactions, gasless permit2 flow, and tier-based API access for sandbox or production.
- [LiFi Intents Provider](/cross-chain/lifi-intents-provider): Cross-chain transfers through the LI.FI intent solver marketplace, where competing solvers fulfill deposits at the best available rate.
- [Cross-Chain: Full Example](/cross-chain/example): End-to-end example of executing a cross-chain transfer — setup, quote, approval handling, transaction submission, and order tracking.
- [Cross-Chain: Frontend Integration](/cross-chain/frontend-integration): Wire the cross-chain SDK into a React/Next.js app with wagmi v2 — a useCrossChainSwap hook covering quotes, approvals, and submission.
- [Order Tracking](/cross-chain/order-tracking): Track cross-chain orders from initiation to completion via OIF OrderStatus events, with both onchain and offchain observation strategies.
- [Cross-Chain: Advanced Usage](/cross-chain/advanced-usage): Aggregator patterns for cross-chain transfers — multi-provider quote fetching, sorting strategies, timeouts, and built-in order tracking.
- [Cross-Chain: API Reference](/cross-chain/api): Function signatures and types for the interop-cross-chain package — providers, aggregator, approval service, and order tracking.
-->

# Across Provider

The Across Protocol provider enables cross-chain token transfers using the Across bridge infrastructure.

**Status**: Active (mainnet + testnet)

## Configuration

| Field        | Type    | Required | Description                                   |
| ------------ | ------- | -------- | --------------------------------------------- |
| `isTestnet`  | boolean | No       | Use testnet API (default: false)              |
| `apiUrl`     | string  | No       | Custom API endpoint URL (overrides isTestnet) |
| `providerId` | string  | No       | Custom provider identifier                    |

Notes:

* `isTestnet` also affects **tracking** defaults (see below).
* `apiUrl` overrides the **quote** endpoint. Tracking uses the standard Across API base URL for the selected network.

## Creating the Provider

```ts twoslash
import { createCrossChainProvider } from "@wonderland/interop-cross-chain";

// Across config is optional - defaults to mainnet
// Mainnet: https://app.across.to/api
// Testnet: https://testnet.across.to/api
const acrossProvider = createCrossChainProvider("across", { isTestnet: true });
```

## Getting Quotes

```typescript
const quotes = await acrossProvider.getQuotes({
    user: "0xYourAddress",
    input: {
        chainId: 11155111,
        assetAddress: "0xInputTokenAddress",
        amount: "1000000000000000000", // 1 token (in wei)
    },
    output: {
        chainId: 84532,
        assetAddress: "0xOutputTokenAddress",
        recipient: "0xRecipientAddress",
    },
    swapType: "exact-input",
});

const quote = quotes[0]; // Select the first quote
```

## Fees

After getting a quote, you can inspect the standardized fee breakdown via `quote.fees`:

```typescript
const quote = quotes[0];

console.log(quote.fees?.bridgeFee); // { amount, amountUsd, token }
console.log(quote.fees?.bridgeFeePct); // percentage (wei-encoded, 1e18 = 100%)
console.log(quote.fees?.originGas); // origin chain gas estimate
```

See the [API reference](/cross-chain/api#quotefees) for the full `QuoteFees` type.

## Executing Transactions

Across quotes always contain transaction steps. After getting a quote, execute the transaction:

```typescript
import { getTransactionSteps } from "@wonderland/interop-cross-chain";
import { createWalletClient, http } from "viem";
import { sepolia } from "viem/chains";

const walletClient = createWalletClient({
    chain: sepolia,
    transport: http(),
    account: yourAccount,
});

const step = getTransactionSteps(quote.order)[0];
const hash = await walletClient.sendTransaction({
    to: step.transaction.to,
    data: step.transaction.data,
    value: step.transaction.value ? BigInt(step.transaction.value) : undefined,
});
console.log("Transaction sent:", hash);
```

## Tracking (Mainnet vs Testnet)

Across tracking is implemented as:

* **Mainnet**: API-based fill tracking (polls `GET /deposit/status?depositTxnRef=<openTxHash>`)
* **Testnet**: Event-based fill tracking (Across testnet API is not reliable)

In both cases, the SDK parses the ERC-7683 open event on the **origin chain**, so you should provide an origin-chain RPC URL for robust tracking.

## Next Step

See a complete working example: [Full Example](/cross-chain/example)

## References

* [Across Protocol Documentation](https://docs.across.to/)
* [API Reference](/cross-chain/api) — full type definitions for quotes, fees, and orders
* [Concepts](/cross-chain/concepts) — how intent-based transfers work