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

# Supported networks

> Blockchains supported by nanopayments for deposits, gas-free payments, and withdrawals

Nanopayments supports gas-free USDC payments on all EVM blockchains listed in
the [Gateway supported blockchains](/gateway/references/supported-blockchains)
table where the **Nanopayments** column is marked **Yes**.

Use the `SupportedChainName` value from the table when initializing
`GatewayClient` or configuring the SDK:

```typescript theme={null}
const client = new GatewayClient({
  chain: "base", // SupportedChainName from the supported blockchains table
  privateKey: "0x...",
});
```

<Note>
  When using `GatewayClient`, deposits and payments are scoped to the blockchain
  you configure on the client. If you want to pay on Base, initialize the client
  for Base and deposit there. To avoid long deposit wait times, use Arc App Kit's
  [Bridge Kit](https://docs.arc.io/app-kit/bridge) to bridge your USDC to a
  fast-finality blockchain before depositing. The
  [Fast deposits](/gateway/references/supported-blockchains#fast-deposits) section
  offers third-party alternatives for faster deposits.
</Note>

## Contract addresses

If you are constructing EIP-712 signatures manually (without the SDK), you need
the contract addresses for your target chain:

* **GatewayWallet address** (used as `verifyingContract` in the EIP-712 domain):
  [EVM contract addresses](/gateway/references/contract-addresses)
* **USDC token address** (used as the `asset` in payment requirements):
  [USDC contract addresses](/stablecoins/usdc-contract-addresses)

The SDK's `CHAIN_CONFIGS` constant provides these values programmatically. See
the [SDK reference](/gateway/nanopayments/references/sdk#chain-configuration)
for details.

## Testnet faucets

To test nanopayments, you need testnet USDC and native gas tokens:

* [Circle Faucet](https://faucet.circle.com) — testnet USDC for supported
  testnet blockchains
* For native gas tokens (required for onchain deposit transactions), use the
  blockchain-specific faucets listed on each testnet's documentation site