/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 request. 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.

for agents

mcp → npx @xenarch/agent-mcp
python → pip install xenarch[agent]
cli → npx xenarch
frameworks → LangChain & CrewAI tools built in.

for publishers

fastapi → pip install xenarch[fastapi]
wordpress → Plugin on GitHub
pay.json → Open spec on GitHub

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?

The “Payment Required” status code — reserved in the HTTP spec since 1997, historically unused. A server returns 402 to signal payment is needed. Xenarch resolves 402 responses automatically 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 the request. 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. The server verifies, the payment settles on-chain, the response is served.

How is Xenarch different from 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, and the 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 with Xenarch?

Via the Xenarch MCP server (@xenarch/agent-mcp), the Python SDK (xenarch[agent]), or the 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, using user-agent, IP, and request-pattern signals. HTTP 402 is returned to those clients only; human traffic is unaffected.