Quickstart

Aegis is a stateless x402 API. No signup, no API keys. You need:

A wallet on Base with a small USDC balance.
A signing client that can produce an X-PAYMENT header. The Coinbase x402 SDK ships clients for Python, TypeScript/JavaScript, Go, and Java.

Both Base mainnet and Base Sepolia (testnet) are supported. Start on Sepolia for free testing before flipping to real USDC.

1. Discover the price list

No payment, no auth.

curl https://x402.aegis-kyt.com/.well-known/x402.json | jq

{
  "name": "Aegis KYT x402 API",
  "services": [
    { "endpoint": "/screen/{chain}/{address}",           "price": "0.10", "asset": "USDC", "network": "base", "available": true  },
    { "endpoint": "/check-address/{chain}/{address}",      "price": "1.00", "asset": "USDC", "network": "base", "available": true  },
    { "endpoint": "/check-transfer/{chain}/{tx_hash}",   "price": "0.50", "asset": "USDC", "network": "base", "available": true  }
  ]
}

2. Probe the quote

Hit any tier path without payment — the server replies 402 with a machine-readable quote.

curl -i https://x402.aegis-kyt.com/screen/eth/0x6b175474e89094c44da98b954eedeac495271d0f

HTTP/2 402
payment-required: <base64-encoded JSON quote>

{}

Decode the payment-required header to get:

{
  "x402Version": 2,
  "accepts": [{
    "scheme":  "exact",
    "network": "eip155:84532",
    "asset":   "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
    "amount":  "100000",
    "payTo":   "0x6d0A788caC92d83FB827CDfb07C0D111e97Acfb6",
    "maxTimeoutSeconds": 300,
    "extra":   { "name": "USDC", "version": "2" }
  }]
}

amount is in USDC base units (6 decimals — 100000 = $0.10).

3. Sign and retry

Use the Coinbase x402 client to sign the quote against your wallet and retry with the X-PAYMENT header.

from x402.client import x402Client
from eth_account import Account
import httpx

# Your wallet (Base Sepolia for testing, real key for mainnet)
account = Account.from_key("0x" + "your-test-key-here")

client = x402Client(account=account)

# httpx client — the x402 client wraps it transparently
async with httpx.AsyncClient() as http:
    response = await client.get(
        http,
        "https://x402.aegis-kyt.com/screen/eth/0x6b175474e89094c44da98b954eedeac495271d0f",
    )
    print(response.json())

import { x402Client } from "@x402/fetch";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount("0xyour-test-key-here");
const client = x402Client({ account });

const res = await client.fetch(
  "https://x402.aegis-kyt.com/screen/eth/0x6b175474e89094c44da98b954eedeac495271d0f",
);
console.log(await res.json());

# 1. Get the quote (decode the payment-required header)
QUOTE=$(curl -is https://x402.aegis-kyt.com/screen/eth/0x6b17... \
        | awk -F': ' '/^payment-required:/ {print $2}' | tr -d '\r')

# 2. Sign the EIP-3009 transferAuthorization off-line (any EIP-712
#    signing tool — too long for this snippet; use the Coinbase SDK).
PAYMENT=$(your-x402-signer "$QUOTE")

# 3. Retry with X-PAYMENT
curl -H "X-PAYMENT: $PAYMENT" https://x402.aegis-kyt.com/screen/eth/0x6b17...

4. Receive the answer

{
  "schema_version": 1,
  "address": "0x6b175474e89094c44da98b954eedeac495271d0f",
  "chain": "ETH",
  "labels": [
    {
      "source":      "provider_a-verdicts",
      "source_name": "provider_a",
      "label":       "DAI Stablecoin Contract",
      "category":    "stablecoin",
      "confidence":  92,
      "source_url":  "https://...",
      "first_seen_at": "2025-08-12T00:00:00Z",
      "last_seen_at":  "2026-04-29T00:00:00Z"
    }
  ],
  "risk": {
    "risk_level":          "none",
    "risk_score":          0,
    "is_risky":            false,
    "risk_categories":     [],
    "source_count":        9,
    "confidence":          94,
    "primary_source_slug": "provider_a-verdicts",
    "label":               "DAI Stablecoin",
    "consensus_found":     true
  }
}

Replay protection is on by default — the same X-PAYMENT header won’t authorize a second call. Sign a fresh one for each request.

Next steps

Authentication deep-dive — exactly what’s in the X-PAYMENT header.
Endpoint reference — per-tier request/response.
Networks — supported {chain} values.
Risk categories — taxonomy returned in risk.risk_categories[] from the screening tiers.
Running pre-send screens at high volume? Switch to V2 API’s POST /v2/screen — same data, settled via subscription quota instead of per-call USDC.

Get started

Authentication

x402 Endpoints (USDC pay-per-call)

V2 Public API

Webhooks (push events)

Methodology

Reference

Other

1. Discover the price list

2. Probe the quote

3. Sign and retry

4. Receive the answer

Next steps

​1. Discover the price list

​2. Probe the quote

​3. Sign and retry

​4. Receive the answer

​Next steps

1. Discover the price list

2. Probe the quote

3. Sign and retry

4. Receive the answer

Next steps