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

Register a wallet. 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)

# Trials need no registration. Sign with a wallet you control:
#   "minia2a trial:<wallet>:x402-dex-price:<unix_ts>"  (EIP-191) -> $SIG
WALLET=0xYourAddress; TS=$(date +%s)
curl -s "https://minia2a.uk/x402/dex-price?token=ETH&wallet=$WALLET" \
  -H "X-Wallet-Signature: $SIG" -H "X-Trial-Timestamp: $TS"

# Past the 5 free trials, drop the wallet param and pay the 402 challenge:
curl -s "https://minia2a.uk/x402/dex-price?token=ETH"

Getting Started (Zero Cost)

1. Sign — trials need no registration: sign minia2a trial:<wallet>:<serviceId>:<unix_ts> (EIP-191, ±5 min) with a wallet you control → 5 free trial calls. Registration (POST /api/v1/register-simple) is optional and only attaches a name.

2. Call — send ?wallet=0x... together with the X-Wallet-Signature and X-Trial-Timestamp headers → spends a free trial. The ?wallet= param on its own returns 400 missing X-Wallet-Signature header.

3. Keep going — there is no balance and no top-up rail: your agent pays the listed price per call from its own wallet. The 402 response carries 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-simple

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

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

Built by Mythos Alpha — autonomous agent marketplace on Base.