c402
Open protocol · live on Ethereum Sepolia · no mock data

Pay for a
private thought.

x402 made any resource payable by any agent. c402 makes any computation confidential and payable - same pattern, one level deeper. A c402 server declares a TEE-attested confidential endpoint; any client pays and consumes it, knowing nothing about the implementation. Two headers on top of x402.

Inspect a live endpoint →Read the protocol
Confidentiality of values - not anonymity of addresses.
the c402 handshake · liveTEE attested
HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: price 0.01 USDC · eip155:11155111
Compute-Required: euint256 → treasury-action · nox/tdx
↓ client pays via x402 · server computes in the TEE
HTTP/1.1 200 OK
PAYMENT-RESPONSE: settled ✓
X-Attestation: #- · commitment …
x402
payment layer
c402
confidential layer
reading live from Sepolia…
Confidential decisions
-
Encrypted events
-
Apps on c402
2
TEE standard
Nox · TDX
For developers

A confidential, paid endpoint in one function. Consume it like a normal fetch.

server · @c402/server
app.post("/decide", c402({
  price: "0.01", token: USDC, network: "eip155:11155111",
  facilitator: FACILITATOR, contract: CDE, payTo: PAY_TO,
  schema: { input: "euint256", output: "treasury-action" },
  compute: async (input) => {
    // runs inside the iExec Nox TEE
    return await decideConfidentially(input);
  },
}));
client · @c402/client
const call = c402Fetch({
  signer, network: "eip155:11155111", rpcUrl,
});
 
const res = await call("http://cde/decide", {
  body: { exposure, signal },
});
 
res.result;  res.attestation;  res.verified.valid;
@c402/spec@c402/server@c402/client@c402/verify
How it works

402 → pay → compute → attest → verify

01
402
An unpaid request returns 402 with PAYMENT-REQUIRED and Compute-Required - price, token, TEE, input/output schema.
02
Pay
The client pays via standard x402 (EIP-3009 USDC), settled by a facilitator. c402 doesn't touch settlement.
03
Compute
The server runs the computation inside the iExec Nox TEE. Inputs, state and reasoning stay encrypted.
04
Attest
The 200 carries X-Attestation - real on-chain artifacts (commitment, tx, handles), not a trust-us blob.
05
Verify
Anyone re-reads the commitment on-chain via @c402/verify. No server cooperation required.
Apps on c402

The protocol is the product. These are the proof.

Confidential Treasury (xCAT)
live on Sepolia
An autonomous treasury for Safe. Agents buy confidential decisions over c402, then execute swaps through unmodified Safe + Uniswap. The first app on the protocol.
Open dashboard →
Confidential Payroll
live on Sepolia
Approve / defer / reject raise decisions against an encrypted budget and policy cap - without revealing the numbers. A second, different computation on the same protocol.
Open dashboard →
Composes with

Privacy added to open protocols - without modifying them

x402
unmodified
The open HTTP 402 payment protocol. c402 adds two headers on top; the payment and settlement legs are pure x402.
iExec Nox
unmodified
Intel TDX TEEs with on-chain handles + ACLs. The confidential compute and the attestations are Nox.
Safe
unmodified
The treasury app custodies funds in a standard Safe; the agent proposes and executes from the Safe itself.
Uniswap
unmodified
Rebalancing swaps route through the standard v3 router - no forks, output lands back in the Safe.

Feel the protocol in 15 seconds

Paste a c402 endpoint, decode its headers, pay, and verify the attestation on-chain.

Open the inspector →
c402 · Confidential compute over x402
Composes x402 · iExec Nox · Safe · Uniswap - unmodified, on Ethereum Sepolia