Cross-Chain Payments

Pay from any chain.

We handle the rest.

Move funds across networks automatically — no bridges, no manual swaps.

You pay once. We handle routing, bridging, and settlement.

We abstract cross-chain payments into a single API call.

~3s

Settlement time

No canonical bridge delays

Bridge fee

Gas sponsored — $0 for user

Native

USDC only

No wrapped tokens ever

Without RelAI

✗ manually bridge funds

✗ manage liquidity across chains

✗ handle failures and delays

✗ switch wallets per chain

✗ track multiple transactions

With RelAI

fund once on any chain

pay anywhere automatically

zero manual steps

one API call

built-in failure recovery

How it works

01You fund on any supported chain

02Agent initiates a payment request

03RelAI routes funds to the destination chain

04Payment settles automatically — ~3 seconds

Liquidity guard: Pool balance is checked before payment is requested. You are never charged for an unavailable route.

Built for agents

Agents don't need to know chains.

They just send a payment request.

RelAI resolves the route, submits the transaction, and confirms settlement.

No chain switching. No wallet management. No manual steps.

Works with Metered API Access — agents get cross-chain payments automatically with a single API key.

Smart routing

RelAI automatically selects the best path for every transfer.

Fastest route — Destination pool is pre-funded — no waiting for on-chain bridge confirmation

Lowest cost path — Gas is sponsored by RelAI facilitator — $0 gas for the user on every chain

Correct destination chain — Route is determined by direction ID — no manual chain selection needed

Auto-rebalancing — Pools rebalance automatically via Circle CCTP in the background — without blocking payouts

Reliability

Automatic retries — Transient failures are retried automatically before surfacing an error

Fallback routes — If a direct route is unavailable, alternative paths are evaluated

Failure recovery built-in — You are never charged if the destination pool cannot fulfill the transfer

Both tx hashes returned — Response includes the source payment tx and destination payout tx with explorer links

Supported networks

SolanaSVM

svm-exactLive

SKALE BaseEVM

exactLive

BaseEVM

exactLive

Query GET /v1/bridge/networks at runtime to get available directions. The bridge UI and SDK use this endpoint automatically.

Fees & limits

Bridge fee	1% of input amount, minimum $0.01
Gas fees	Sponsored by RelAI — $0 for user
Minimum	$0.05 USDC
Maximum	$1 USDC per transaction (beta)
Settlement time	~3 seconds on destination chain

Bridge UI

Available at /bridge. Supports Phantom (Solana) and MetaMask / any EVM wallet (SKALE Base).

01Select direction: Solana → SKALE Base or SKALE Base → Solana

02Connect your source wallet

03Enter amount and destination wallet address

04Click Bridge — approve the x402 payment. USDC arrives within seconds.

SDK integration

Use createX402Client from @relai-fi/x402 — it handles the 402 payment automatically.

Solana → SKALE Base (Node.js agent)

import { createX402Client } from '@relai-fi/x402';
import { Keypair } from '@solana/web3.js';

const keypair = Keypair.fromSecretKey(Buffer.from(process.env.SOLANA_KEY!, 'base64'));
const x402 = createX402Client({
  wallets: {
    solana: {
      publicKey: keypair.publicKey,
      signTransaction: async (tx: any) => { tx.sign([keypair]); return tx; },
    },
  },
  defaultHeaders: { 'X-Service-Key': process.env.RELAI_SERVICE_KEY! },
});

const res = await x402.fetch(
  'https://api.relai.fi/v1/bridge/solana-to-skale-base',
  {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ amount: 10.0, destinationWallet: '0xYourSkaleBaseAddress' }),
  }
);
const result = await res.json();
// result.paymentTxHash  — Solana payment tx
// result.txHash         — SKALE Base payout tx
console.log('Payout:', result.explorerUrl);

SKALE Base → Solana (Node.js agent)

import { ethers } from 'ethers';
import { createX402Client } from '@relai-fi/x402';

const signer = new ethers.Wallet(process.env.EVM_KEY!, new ethers.JsonRpcProvider(process.env.SKALE_RPC_URL));
const x402 = createX402Client({
  wallets: {
    evm: {
      address: signer.address,
      signTypedData: (domain: any, types: any, message: any) =>
        signer.signTypedData(domain, types, message),
    },
  },
  defaultHeaders: { 'X-Service-Key': process.env.RELAI_SERVICE_KEY! },
});

const res = await x402.fetch(
  'https://api.relai.fi/v1/bridge/skale-base-to-solana',
  {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ amount: 5.0, destinationWallet: 'YourSolanaAddress' }),
  }
);
const result = await res.json();
console.log('Payout:', result.explorerUrl); // solscan.io

Management API

Requires X-Service-Key header. Routes are config-driven — new networks appear without changing endpoints.

GET/v1/bridge/networks

List all enabled bridge directions

GET/v1/bridge/quote

Fee and net output for a given amount (params: amount, from, to)

GET/v1/bridge/balances

Current USDC liquidity on all networks

POST/v1/bridge/:direction

Execute bridge. Returns 402 — handled automatically by x402 SDK.

Successful bridge response

{
  "success": true,
  "direction": "solana-to-skale-base",
  "destinationWallet": "0xYourSkaleAddress",
  "amountOutUsd": 9.99,
  "txHash": "0xabc123...",
  "explorerUrl": "https://skale-base-explorer.skalenodes.com/tx/0xabc123...",
  "paymentTxHash": "5Kq7...",
  "paymentExplorerUrl": "https://solscan.io/tx/5Kq7..."
}

Error reference

503insufficient_liquidity

Destination pool cannot fulfill the transfer. Returned before payment is requested — you are never charged. Check /v1/bridge/balances and retry.

402Payment Required

Standard x402 response. Handled automatically by createX402Client.

400Validation error

Invalid amount or destinationWallet format. EVM addresses: 0x... · Solana: base58.

Error handling in SDK

try {
  const res = await x402.fetch('https://api.relai.fi/v1/bridge/solana-to-skale-base', {
    method: 'POST',
    body: JSON.stringify({ amount: 10.0, destinationWallet: '0x...' }),
  });
  const result = await res.json();
} catch (err) {
  if (err.message.includes('insufficient_liquidity')) {
    // Check available liquidity and retry later
    const balRes = await fetch('https://api.relai.fi/v1/bridge/balances',
      { headers: { 'X-Service-Key': process.env.RELAI_SERVICE_KEY! } });
    const { balances } = await balRes.json();
    console.log('Available on SKALE Base:', balances['skale-base']);
  }
}