> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bridg.now/llms.txt
> Use this file to discover all available pages before exploring further.

# Bridge tokens

> Move USDC from Base to Arbitrum: quote, build, sign with viem, submit, wait.

## Prerequisites

* The [TypeScript project](/guides/typescript-setup), which provides `src/evm.ts`.
* A Base wallet holding USDC and ETH for gas.

## Script

Save as `src/bridge-tokens.ts` and run with `npx tsx src/bridge-tokens.ts`.

```typescript src/bridge-tokens.ts theme={null}
import { isBridgError } from '@kernlog/bridg-sdk';
import type { Hex } from 'viem';
import { account, bridg, signEvmStep } from './evm';

async function main() {
  // 1. Quote: 25 USDC on Base to USDC on Arbitrum
  const quote = await bridg.getQuote({
    fromChain: 'base',
    toChain: 'arbitrum',
    fromToken: 'USDC',
    toToken: 'USDC',
    amountAtomic: '25000000',
    sender: account.address,
    recipient: account.address,
  });
  if (!quote.best) throw new Error(`no executable route: ${quote.rejected.map((r) => r.code).join(', ')}`);
  console.log(`${quote.best.venue} delivers ${quote.best.amountOutAtomic} in ~${quote.best.estimatedSeconds}s`);

  // 2. Build the winner
  const build = await bridg.buildTransfer({ decisionId: quote.decisionId });

  // 3. Sign every step in order. Only `main` moves the order; the others are approvals and the fee.
  let mainHash: Hex | undefined;
  for (const step of build.steps) {
    const hash = await signEvmStep(step);
    if (step.step === 'main') mainHash = hash;
  }
  if (!mainHash) throw new Error('build carried no main step');

  // 4. Report the hash
  await bridg.submitTransfer(build.transferId, { txHash: mainHash, step: 'main' });

  // 5. Wait for delivery
  const transfer = await bridg.waitForTransfer(build.transferId, {
    onUpdate: (t) => console.log(t.status),
  });
  console.log(transfer.status, transfer.destinationTxHash);
}

main().catch((error) => {
  if (isBridgError(error)) console.error(error.code, error.message, error.details);
  else console.error(error);
  process.exit(1);
});
```

## Notes

* Wallets that support EIP-5792 batching can sign the `fee` and `main` steps as one bundle; `build.feeBatch` names the steps. Sequential signing, as above, is always correct.
* `expectedOutAtomic` on the build equals the `amountOutAtomic` you were quoted.
* A `quote_drifted` or `quote_expired` error on build means the price moved. Quote again.

## Endpoints used

| SDK               | Endpoint                                                            |
| ----------------- | ------------------------------------------------------------------- |
| `getQuote`        | [`POST /bridge/quote`](/api-reference/quote/quote)                  |
| `buildTransfer`   | [`POST /bridge/build`](/api-reference/quote/build)                  |
| `submitTransfer`  | [`POST /bridge/transfers/{id}/submit`](/api-reference/quote/submit) |
| `waitForTransfer` | [`GET /bridge/transfers/{id}`](/api-reference/quote/transfer)       |