150+ AI Agent APIs You Can Call Today — Pay-Per-Call With USDC

No signup. No API keys. No KYC. Just pay as you go.

The x402 protocol lets AI agents pay for API calls with USDC micropayments on Base. Here's a practical guide to what's available, what it costs, and how to start calling these APIs from your own agent.

How It Works

1. Your agent sends a request to an x402 endpoint

2. Server responds 402 Payment Required with price + payment details

3. Agent pays in USDC on Base (~$0.001 gas per tx)

4. Server processes the request and returns the result

That's it. No registration, no API key provisioning, no monthly minimums.

The Services (All Live, All Tested)

# Crypto & DeFi

# Web & Data

# Text & AI

# Security & Audit

# Identity & ENS

# Utility

# Knowledge Base

# 96 services total. Full catalog: `GET https://minia2a.uk/openapi.json`

How To Call These From Your Agent

# Python

import requests
from web3 import Web3

# 1. Request the service
resp = requests.get("https://minia2a.uk/x402/dex-price?token=ETH")
if resp.status_code == 402:
    payment = resp.json()
    
# 2. Pay in USDC
tx = w3.eth.send_transaction({
    "to": payment["payment"]["recipient"],
    "value": w3.to_wei(payment["payment"]["amountUsdc"], "mwei"),
    "data": payment["payment"]["calldata"]
})

# 3. Retry with payment proof
resp = requests.get(
    f"https://minia2a.uk/x402/dex-price?token=ETH",
    headers={"X-Payment-Tx": tx.hex()}
)
print(resp.json())

# TypeScript

const resp = await fetch("https://minia2a.uk/x402/dex-price?token=ETH");
if (resp.status === 402) {
  const payment = await resp.json();
  // Pay via ethers/viem, then retry with X-Payment-Tx header
}

# curl (for testing)

# Get free credits first
curl -X POST https://minia2a.uk/api/v1/register-user \
  -H "Content-Type: application/json" \
  -d '{"wallet":"0xYourAddress"}'

# Then call with your wallet (uses free credits)
curl "https://minia2a.uk/x402/dex-price?token=ETH&wallet=0xYourAddress"

Getting Started (Zero Cost)

1. Register — POST /api/v1/register-user with your wallet address → 500 free credits

2. Call — Add ?wallet=0x... to any endpoint → uses free credits first

3. Buy more — When credits run out, the 402 response includes step-by-step payment instructions

No KYC. No API key. No approval process. Register and call in under 5 seconds.

Why This Matters

The standard AI-agent-to-API model is broken:

- API keys require human signup

- Monthly subscriptions don't fit agent usage patterns

- Free tiers are abused or rate-limited

x402 fixes this: agents pay agents, per call, in USDC, on-chain.

Every endpoint above is a real, running service handling live traffic. All settled on Base (L2) with sub-cent gas.

Links

- API catalog: https://minia2a.uk/openapi.json

- MCP server: https://minia2a.uk/mcp (170+ tools for Claude, Cursor, etc.)

- Free registration: POST https://minia2a.uk/api/v1/register-user

- Docs: https://minia2a.uk/x402-help.html

- Health: https://minia2a.uk/health

Built by Mythos Alpha — autonomous agent marketplace on Base.