Base Now Supports Multiple Tokens - USDT, EURC, DAI, cbETH, and cbBTC Alongside USDC

Base has been supported by RelAI since launch - but until now, only USDC. Starting today, RelAI APIs on Base accept multiple tokens: USDC, USDT, EURC, DAI, cbETH, and cbBTC.

No configuration required. If your API is on Base with the RelAI facilitator, all supported tokens are automatically included in every 402 response.

What Changed

Previously, a Base API configured with RelAI would return a single accept entry:

{ network: "eip155:8453", asset: "0x833589f...USDC", amount: "10000" }

Now it returns an accept for every supported token:

{ network: "eip155:8453", asset: "0x833589f...USDC",  amount: "10000"         }
{ network: "eip155:8453", asset: "0xfde4C96...USDT",  amount: "10000"         }
{ network: "eip155:8453", asset: "0x60a3E35...EURC",  amount: "9200"          }
{ network: "eip155:8453", asset: "0x50c5725...DAI",   amount: "10000000000000000000" }
{ network: "eip155:8453", asset: "0x2Ae3F1E...cbETH", amount: "3000000000"    }
{ network: "eip155:8453", asset: "0xcbB7C00...cbBTC", amount: "10000"         }

The client picks whichever token they hold. RelAI resolves the correct atomic amount for non-USD assets (cbETH, cbBTC, EURC) using a live price feed. The merchant always receives the equivalent USD value — token selection is invisible to the API provider.

Supported Tokens on Base

How Pricing Works

You still set a single USD price per endpoint. RelAI converts that price to the correct token amount at settlement time:

• USDC / USDT / DAI — 1:1 USD peg, no conversion needed
• EURC — live EUR/USD rate applied
• cbETH — live ETH/USD rate applied
• cbBTC — live BTC/USD rate applied

For API Providers

Nothing to do. If your API is already on Base with RelAI, multi-token is enabled automatically. Open your API in the dashboard to confirm — the token selector now shows Multi-token supported (6) with a breakdown of all accepted tokens on hover.

If you are creating a new API, select Base as the network and RelAI as the facilitator. All tokens are included by default.

For API Consumers

Any x402-compatible client that supports EIP-3009 token selection will automatically pick the best token from the 402 response. The RelAI SDK handles this transparently:

import { createX402Client } from '@relai-fi/x402'
const client = createX402Client({
  evmWallet: { address, signTypedData },
})
// Automatically pays with whichever supported token the wallet holds
const response = await client.fetch('https://your-api.x402.fi/endpoint')

No changes needed on the consumer side.

Multi-token Base support is live now. Open the dashboard to see it in action.

Further Reading

Tokens

• USDC on Base — Circle USD Coin
• USDT on Base — Tether USD
• EURC on Base — Circle Euro Coin
• DAI on Base — Dai Stablecoin
• cbETH on Base — Coinbase Wrapped Staked ETH
• cbBTC on Base — Coinbase Wrapped BTC

Protocol

• x402 payment protocol — HTTP 402 standard for machine-to-machine payments
• Supported Networks & Tokens — full compatibility matrix
• RelAI SDK on npm — @relai-fi/x402