Build cross-chain apps with Avail Nexus — accept payments from any chain, swap tokens across ecosystems, and execute contracts remotely.
Nexus lets your app move assets and execute transactions across chains without requiring users to bridge manually. Your users see their balances across every supported chain, review one quote, and sign once. Nexus turns that into an intent that a provider fills on the destination chain, usually in seconds.
Quick Look — How the SDK Works
TypeScript
import { createNexusClient } from '@avail-project/nexus-core';import { parseUnits } from '@avail-project/nexus-core/utils';// 1. Create the client and connect a walletconst client = createNexusClient({ clientId: 'your-app-name', network: 'mainnet' });await client.initialize();await client.setEVMProvider(provider); // EIP-1193 provider from your wallet connector// 2. See balances across all supported chainsconst balances = await client.getBalances();// 3. Get 100 USDC on Arbitrum, funded from any chainconst usdc = { chainId: 42161, tokenAddress: '0xaf88d065e77c8cC2239327C5EDb3A432268e5831' } as const;const token = await client.getToken(usdc);await client.swapWithExactOut( { toChainId: usdc.chainId, toTokenAddress: usdc.tokenAddress, toAmountRaw: parseUnits('100', token.decimals), }, { hooks: { // Show the quote, then call allow() when the user confirms onIntent: ({ quote, allow, deny }) => allow(), }, },);
What Changes for Your Users
Without Nexus
With Nexus
User bridges manually, switches chains, manages gas per chain
User reviews one quote and signs once — Nexus routes funds across chains
Dev writes bridge logic per chain pair
Dev calls one SDK method with a destination token and amount
Node.js 18+, a package manager (npm/pnpm/yarn), and an EVM wallet (MetaMask, WalletConnect, etc.).
How Nexus Works
When a user starts a cross-chain action, Nexus handles the flow behind one review and one signature:
The SDK Requests a Quote
The user asks for "100 USDC on Arbitrum". The Nexus middleware picks the source balances, the fees, and one provider to fill the intent.
The User Approves and Signs Once
Your app shows the intent through the onIntent hook. The user approves and signs one message. Token approvals and native-token deposits may add wallet prompts on source chains.
The Provider Fills on the Destination Chain
The signed intent is submitted and the source funds are deposited. The provider delivers the output on the destination chain, usually within seconds. For Nexus routes, a solver fronts its own capital.
Settlement Happens in the Background
For Nexus routes, the solver is repaid from the deposited source funds through an on-chain settlement authorized by Nexus validators. The user's transfer is already complete.
Note
Each quote is filled by one provider: Nexus solvers (nexus-v2), Mayan (mayan), or Relay (relay). The middleware picks it per quote, and your integration code stays the same.
Supported Chains & Tokens
Nexus supports swaps, same-asset bridging, and contract execution across major EVM chains, including Ethereum, Arbitrum, Base, Optimism, and Arc. Call client.getSupportedChains() and client.getTokens() for the live list.