x402 Conformance runs on your own machine — the client starts it, so there is no endpoint to ping. Last commit 25 Oct 2026.
x402 payment safety checks: validate a 402 answer, prove a server never serves before settlement.
What the code does
We read the source, 1 h ago · rules 995398eba69f
What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.
p = subprocess.run(["node", "--no-warnings", "payer.mjs", json.dumps(requirements)], cwd=NODE_DIR, env=self.env,
return dict(eval(compile(ast.Expression(node.value), "spec.py", "eval"), env)) # noqa: S307
with open(os.path.join(root, path), encoding="utf-8") as f:
p = subprocess.run(cmd, shell=True, cwd=ROOT, capture_output=True, text=True, timeout=timeout)
const c = spawn(this.cmd, { shell: true, stdio: this.stdio, detached: true, env: this.env });
env = dict(os.environ, X402C_KEYS=a.keys, X402C_RPC=a.rpc)
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
This code can reach further than it looks
We found places where it runs commands, builds paths or queries from values it is given. None of that is a flaw by itself — it becomes one when the code changes, and code changes quietly between releases. We re-read it on every one.
Connect this server
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add x402-conformance -- npx -y x402-conformance-mcp{
"mcpServers": {
"x402-conformance": {
"command": "npx",
"args": [
"-y",
"x402-conformance-mcp"
]
}
}
}[mcp_servers.x402-conformance]
command = "npx"
args = ["-y", "x402-conformance-mcp"]{
"mcpServers": {
"x402-conformance": {
"command": "npx",
"args": [
"-y",
"x402-conformance-mcp"
]
}
}
}{
"servers": {
"x402-conformance": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"x402-conformance-mcp"
]
}
}
}Alternatives to x402 Conformance
same job, measured the same wayPre-payment safety gate for x402 agents: PII screening, spend policy, replay checks before signing.
Read-only on-chain receipt check for x402 payments; confirm settlement before trusting a tx.
Surface contracts: API behavior evidence, x402 pre-payment check, MCP server preflight
Noncustodial Base x402 payment control and seller settlement recovery
Verify x402 payment endpoints before an AI agent pays: scam scan, on-chain checks, trust scores.
Screens x402 payments before settlement for injected payee addresses and sellers who never deliver.
Check stablecoin and x402 payments before an AI agent pays: approve, hold or reject.
Verified XRP Ledger answers with proof: payment, send, and issuer checks. Pay per call via x402.
x402 Conformance — questions
Answers built from our own checks of this server.