/xenarch

Payment infrastructure for the agentic internet

how it works

402 → If a resource returns HTTP 402, Xenarch resolves it.
pay → x402 micropayments. USDC on Base. Sign and retry.
get paid → Serve /.well-known/pay.json. Done.
pricing → pay.json is the new robots.txt.
detect → AI crawler & bot detection. Humans pass through.

what is x402

HTTP 402 → “Payment Required” — reserved in the HTTP spec since 1997. Xenarch is how it finally ships.
x402 → Open protocol that resolves HTTP 402 with a signed USDC micropayment. Introduced by Coinbase in 2025.
pay-per-crawl → Publishers charge AI crawlers per page or per path. No subscriptions, no API keys — just 402 and a signed payment.
vs cloudflare → Same idea as Cloudflare pay-per-crawl, but non-custodial. Payment settles on-chain, publishers are paid directly, 0% fee.
api monetization → Charge per call instead of per month. Stateless, keyless, standard HTTP. Read the HTTP 402 explainer →

api monetization

model → API monetization on Xenarch is per-request, not subscription. The API returns HTTP 402 with a price, the caller pays USDC on Base L2, access is granted — no account, no API keys.
vs api gateways → Apigee, Kong, and AWS API Gateway monetize via subscription dashboards and key provisioning. Xenarch monetizes via the HTTP 402 spec — per-request, on-chain, zero account creation.
vs stripe / paypal → No 2.9% + $0.30 minimum. No card-on-file. USDC settles in real time on Base L2. 0% platform fee, hard-capped at 0.99% on-chain.
fastapi → @require_payment(price_usd="0.003") on any route. The decorator returns 402, verifies the on-chain payment, and grants access with a Bearer token.
audience → Per-request API monetization for AI agents, bots, and humans uniformly — from the long tail of Python APIs to enterprise endpoints. Works on any host, any stack.

build

mcp → npx @xenarch/agent-mcp — MCP server for Claude, Cursor, Windsurf.
python → pip install xenarch — agent + publisher SDK.
frameworks → LangChain & CrewAI tools built in.
pay.json → Open spec on GitHub — machine-readable pricing.

publish

wordpress → Plugin on GitHub — drop-in, no code.
fastapi → pip install xenarch[fastapi] — payment middleware.

manage

cli → npx xenarch — wallet, sites, pricing.
mcp → Same MCP server — manage from Claude or Cursor.
docs → docs.xenarch.com

contract

address → 0xC6D3…62ae
network → Base mainnet · chain 8453
asset → USDC
fee → 0%

properties

Non-custodial

Smart contract splits payment on-chain. Xenarch never holds money. Verify on Basescan.

0% fee

What the agent pays is what you receive.

AI client identification

Identifies AI crawlers, LLM training bots, and HTTP clients. Humans pass through.

listed on

smithery · glama · npm · pypi · github

faq

what is http 402
“Payment Required” status code, reserved in the HTTP spec since 1997 and historically unused. A server returns 402 to signal payment is needed. Xenarch resolves 402 responses via x402 micropayments.
what is x402
Open protocol for resolving HTTP 402. The client signs an EIP-712 payment authorization, sends it in the X-Payment header, and retries. USDC settles on Base L2.
how does pay-per-crawl work
Publishers gate resources behind HTTP 402. AI crawlers request the resource, receive 402 plus pricing, sign a USDC payment on Base, and retry. Server verifies, payment settles on-chain, response served.
xenarch vs cloudflare pay-per-crawl
Cloudflare is custodial and takes a cut. Xenarch is non-custodial: an immutable splitter contract pays publishers directly on-chain, Xenarch never holds funds, fee is 0%.
what is pay.json
Open standard for machine-readable pricing, served at /.well-known/pay.json. AI agents read it to discover resource prices before making a request. Robots.txt for payments.
which network and asset
USDC on Base mainnet, chain 8453. Payments route through an immutable splitter contract — verifiable on Basescan.
how do ai agents pay
Via the Xenarch MCP server (@xenarch/agent-mcp), Python SDK (xenarch[agent]), or built-in LangChain and CrewAI tools. All handle x402 negotiation, signing, and retry transparently.
does xenarch detect ai bots
Yes — AI crawler, LLM training bot, and autonomous HTTP client detection via user-agent, IP, and request-pattern signals. HTTP 402 is returned to those clients only; human traffic is unaffected.