x402

Pay-per-request API access using USDC on Base — no API key required

The Vaults.fyi API supports the x402 payment protocol for keyless, pay-per-request access using USDC on Base. This is ideal for AI agents and autonomous systems that need programmatic access without managing API keys.

How it works

1. Send a request with the x-402-auth: true header (no API key needed)

2. Receive a 402 Payment Required response with payment details

3. Sign a USDC payment on Base using your wallet

4. Resend the request with the X-Payment proof header

5. Receive a 200 response with data

Use the x402 Python or JS library to handle the payment flow automatically.

Quick start

Install the x402 client library and make your first request:

JavaScript

import { wrapAxios } from "x402/axios";
import axios from "axios";
import { createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { base } from "viem/chains";

const account = privateKeyToAccount(process.env.PRIVATE_KEY);
const walletClient = createWalletClient({
  account,
  chain: base,
  transport: http(),
});

const client = wrapAxios(axios, walletClient);

const response = await client.get("https://api.vaults.fyi/v2/vaults", {
  headers: { "x-402-auth": "true" },
});

Python

For a complete working example, see the Agentic DeFi repo.

Pricing

All prices are in USDC on Base, charged per request.

Price	Endpoints
$0.005	/v2/networks, /v2/vaults, /v2/tags, /v2/assets, /v2/curators
$0.01	/v2/vaults/{network}/{address}, /v2/vaults/{network}/{address}/performance
$0.02	/v2/detailed-vaults/{network}/{address}, /v2/positions/{address}
$0.025	/v2/deposit-options/{address}, /v2/idle-assets/{address}, /v2/best-vault/{address}
$0.05	/v2/transactions/*, /v2/transactions/rewards/claim/{address}
$0.75	/v2/detailed-vaults (paginated list of all vaults)
Free	/v2/health

/v2/historical/* endpoints are not available via x402 and require an API key.

Payment is in USDC raw units (6 decimals). For example, 5000 = $0.005 USDC. The 402 response always contains the current maxAmountRequired. Prices are subject to change.