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

# Base

> EVM asset identifiers, wallet registration, and offramp funding on Base.

![Base](https://mintcdn.com/etherfuse/XRSchVFGUgreQatD/img/chains/base.svg?fit=max\&auto=format\&n=XRSchVFGUgreQatD\&q=85\&s=2e66b7c72272a611f386d0912e488507)

We support onramps and offramps on Base. Base is an EVM chain, so assets are plain ERC-20 contracts. The end-to-end flows are in the [Onramps](https://docs.etherfuse.com/v2/guides/testing-onramps.md) and [Offramps](https://docs.etherfuse.com/v2/guides/testing-offramps.md) guides.

## Supported operations

| Operation | Supported |
| - | - |
| Onramp (fiat → token) | ✓ |
| Offramp (token → fiat) | ✓ |
| Swap (token → token) | ✗ Swaps run on [Stellar](https://docs.etherfuse.com/v2/guides/chains/stellar.md), [Solana](https://docs.etherfuse.com/v2/guides/chains/solana.md) and [Monad](https://docs.etherfuse.com/v2/guides/chains/monad.md) |

We quote stablebonds on Base. Stablecoin (for example USDC) onramps and offramps run on Solana, Stellar and Monad.

## Asset identifiers

Base assets are identified by the **raw token contract address only**, for example `0xcC77c598d42f2f78Beb42C91d12B9d4041a5cE29`.

> [!WARNING]
>
> **Do not prefix with a symbol.** A `SYMBOL:0x...` identifier (the Stellar-style format) fails on an EVM chain. Pass only the `0x...` address, the token's `asset` from [`GET /supported_assets?chain=base`](https://docs.etherfuse.com/v2/api-reference/assets/list-supported-assets).

## Stablebond addresses

Live token-contract addresses for every stablebond on Base, each linked to Basescan:

## Register a Base wallet

Register the wallet as a payment account with `accountDetails` of kind `address` and `chain` `base`. Set `$ORGANIZATION_ID` to the organization that owns the wallet: your own organization or a customer organization. See [Organizations in the route](https://docs.etherfuse.com/v2/overview.md#organizations-in-the-route).

```bash theme={null}
curl -X POST https://api.sand.etherfuse.com/organization/$ORGANIZATION_ID/payment_account \
  -H "Authorization: <api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "kind": "wallet",
    "label": "Base wallet",
    "accountDetails": {
      "kind": "address",
      "address": "0xf82567432381D1326484E5A9140ABCa4294f82D0",
      "chain": "base"
    }
  }'
```

Use the returned `id` as the `source` or `destination` of a [quote](https://docs.etherfuse.com/v2/api-reference/quotes/create-quote.md). An EVM address is valid on every EVM chain, so the account's `rails` can list more than one EVM chain. Set `sourceRail` or `destinationRail` to `base` in the quote to pick this chain.

## Offramps

On a Base offramp, the order's `fundingInstructions.rail` is `base`, and `fundingInstructions.destination` gives the `address` to send the token to. The source asset is an ERC-20 token. When `preparedTransaction` is present, its `transaction` is an unsigned EIP-1559 transaction, `0x`-prefixed hex, that calls the token's `transfer` from the customer's wallet. The customer signs it, submits it and pays the gas in ETH. Otherwise, send the order's `source.amount` of `source.asset` to `address`. The prepared transaction uses the wallet's next nonce, so it goes stale if the wallet sends another transaction first. Then call [`POST /organization/{organizationId}/order/{id}/funding_instructions/refresh`](https://docs.etherfuse.com/v2/api-reference/orders/refresh-funding-instructions) and sign the new one. See [Offramps](https://docs.etherfuse.com/v2/guides/testing-offramps.md).

## Related

> [card] [Onramps](https://docs.etherfuse.com/v2/guides/testing-onramps.md)

> [card] [Offramps](https://docs.etherfuse.com/v2/guides/testing-offramps.md)


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