# AgentRouter — Base Sepolia

> Base Sepolia testnet. Wallet setup and spending require the owner's authorization. Follow one wallet path.

Testnet network details, funding, gas and purchase checks using the existing wallet guides.

[Human guide](https://docs.agentrouter.cc/networks/base-sepolia) · [Pricing](https://agentrouter.cc/pricing#agents) · [Documentation index](https://docs.agentrouter.cc/llms.txt)

## Base Sepolia guide

Use **Base Sepolia testnet** for the documented AgentRouter purchase flow. Fund your agent wallet with test tokens, not real funds. The [model catalog](https://docs.agentrouter.cc/use/models) displays real inference prices.

Choose the [MetaMask](https://docs.agentrouter.cc/wallets/metamask) or [Coinbase](https://docs.agentrouter.cc/wallets/coinbase) guide for wallet setup and the runnable purchase steps. [Mainnet documentation](https://docs.agentrouter.cc/networks/mainnet) is work in progress, not an alternative purchase procedure.

## Network details

| Setting | Value |
|---|---|
| Network | Base Sepolia |
| Chain ID | `84532` |
| x402 network | `eip155:84532` |
| RPC | [https://sepolia.base.org](https://sepolia.base.org) |
| Explorer | [Base Sepolia explorer](https://sepolia.basescan.org/) |
| Payment asset | Base Sepolia test USDC |
| USDC contract | `0x036CbD53842c5426634e7929541eC2318f3dCF7e` |

Use Base Sepolia only, even if your wallet also lists mainnets. Keep USDC and any test ETH on this network.

## Get test USDC

First obtain your agent wallet's public address: [MetaMask wallet check](https://docs.agentrouter.cc/wallets/metamask#metamask-wallet) or [Coinbase address](https://docs.agentrouter.cc/wallets/coinbase#coinbase-address). For MetaMask, use the separate agent wallet, not your personal phone wallet.

With the wallet owner's approval, open the [Circle faucet](https://faucet.circle.com/).

1. Select **USDC** and **Base Sepolia**.
2. Paste your wallet's EVM address.
3. Click **Send 20 USDC** and wait for confirmation.

Already have Base Sepolia test USDC in another wallet? You can transfer it to this address instead. Use test tokens only; do not buy or send real funds for this setup.

If Circle is unavailable, follow the **UI (CDP Portal)** section of [Coinbase's faucet instructions](https://docs.cdp.coinbase.com/faucets/introduction/quickstart#ui-cdp-portal). Sign in to a Coinbase Developer Platform account, open **Faucets**, select **Base Sepolia** and **USDC**, paste the same EVM address, and click **Claim**. This requires a CDP developer account, separate from the wallet's email login.

After confirmation, [check the MetaMask balance](https://docs.agentrouter.cc/wallets/metamask#metamask-balance) or [check the Coinbase balance](https://docs.agentrouter.cc/wallets/coinbase#coinbase-balance). In MetaMask, `unpriced` and `totalValue: 0` can reflect missing testnet prices, not an empty wallet. Read the token's `amount` and network before funding again.

## Gas and test ETH

The documented USDC x402 flow has the facilitator submit the settlement transaction and pay its gas. A zero-ETH purchase was not independently tested in the supplied Coinbase walkthrough; its successful purchase does not prove that case. See [who pays x402 gas](https://docs.cdp.coinbase.com/x402/support/faq).

Only if another transaction requires unsponsored gas, follow the [optional test ETH instructions](https://docs.agentrouter.cc/wallets/coinbase#coinbase-eth). Use the same public EVM address and Base Sepolia network. Never provide a seed phrase or private key to a faucet.

## Wallet checks

- **MetaMask:** [check authentication, wallet and allowed chains](https://docs.agentrouter.cc/wallets/metamask#metamask-wallet). A zero daily USD limit does not guarantee zero x402 spending: signatures are excluded from that limit. Obtain the wallet owner's spending approval.
- **Coinbase:** [check smart-account deployment](https://docs.agentrouter.cc/wallets/coinbase#coinbase-deployed). This purchase path requires an already-deployed account. Stop on **NOT DEPLOYED**, **CHECK FAILED**, or an error. Funding the address alone is not proof of deployment.

## Purchase and settlement

[Read the offer with MetaMask](https://docs.agentrouter.cc/wallets/metamask#01-quote) or [Coinbase](https://docs.agentrouter.cc/wallets/coinbase#01-quote) before authorizing payment. The documented offer uses `exact`, network `eip155:84532`, the USDC contract above and amount `1000000` (1 test USDC). Inspect the current offer and recipient; stop if the terms differ from what you intend to buy. This is access credit, not the price of one model request.

Follow the [MetaMask purchase step](https://docs.agentrouter.cc/wallets/metamask#03-settle) or [Coinbase purchase step](https://docs.agentrouter.cc/wallets/coinbase#03-settle) once, with the owner's approval. Keep the response, receipt and bearer key private.

Check the receipt's transaction on the [Base Sepolia explorer](https://sepolia.basescan.org/): it should show a successful USDC transfer from your agent wallet to the recipient in the offer. If payment or delivery is uncertain, [stop and inspect the saved result](https://docs.agentrouter.cc/troubleshooting#missing-payment). Do not repeat a payment to recover a key.

## Use your key

With a purchased key, follow the shared [Discover models](https://docs.agentrouter.cc/use/models), [OpenAI-compatible API](https://docs.agentrouter.cc/use/openai) or [Anthropic-compatible API](https://docs.agentrouter.cc/use/anthropic) guide. The post-purchase steps are the same for both wallets.