Your Agent Pays. No Card. No Key. No Human.

Every one of our 63 tools speaks the x402 protocol: call it with no key, get a 402 Payment Required with exact USDC payment instructions, pay on-chain, retry, done. Autonomous payments on Base and Polygon.

Get a free API key — 25 instant credits Try it live — no key Buy credits — packs from $9 Connector: archtools.dev/mcp

How an x402 call works

# 1. Agent calls a tool with no credentials
curl -X POST https://archtools.dev/v1/tools/crypto-price \
  -H "Content-Type: application/json" -d '{"symbol":"BTC"}'

# 2. Server answers 402 Payment Required with machine-readable terms:
#    amount (e.g. $0.010 USDC), asset contract, pay-to address, network

# 3. Agent pays USDC on-chain (Base is ~$0.01 gas), retries the call
#    with the PAYMENT-SIGNATURE header (x402 v2; legacy v1 X-PAYMENT
#    payloads still accepted) — and gets the result. No signup ever.

Machine-readable discovery of every priced endpoint lives at /.well-known/x402. Protocol spec: x402.org.

Base and Polygon, stable pricing

Pay in USDC on Base or Polygon. Tool calls start at $0.010; every price is published upfront in the discovery document and matches what you're charged.

crypto-price — $0.010 per call
web-search (AI-synthesized answer) — $0.025 per call
ai-generate (Claude text generation) — $0.040 per call
research-report — $0.055 per call
Full price list: Web & Data · Crypto · AI & Media · Utilities

Why x402 instead of API keys?

Zero onboarding

An autonomous agent can't click an email verification link or type a credit card. With x402 it just pays and works.

True pay-per-use

No subscription, no minimum, no expiring trial. One call costs one price, settled in USDC.

Keys still welcome

Prefer credits? Sign up free — 100 credits, 25 instant — and use one Bearer key across all 63 tools.

Deep-dive integration guide with wallet setup and code samples: x402 developer guide.