Address-poisoning check before you send USDC on Base

Address-poisoning check before you send USDC on Base. Body {from, to} (or sender/recipient; chain=base, token=USDC only, others 400 not charged; optional contacts/known_addresses): scans the sender's recent Base USDC transfers for lookalikes (same first/last 4 hex) plus dust/zero-value transfers. No sender? {recipient, known_addresses} = offline contacts check; {address} alone scans its own history for poisoning signs. Returns risk low/medium/high, lookalikes, reasons, coverage.

Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.

Endpoint

POST https://paycheck.hectichustle.workers.dev/address/check

Our checks, last 30 days

We never call tools that send, buy, move money or file anything, not even without paying.

Example input (from the provider)

{
  "body": {
    "from": "0x9D42EbA8868CFd38A50Ba615ee0cf903F1BBeCE9",
    "to": "0x509E55c4F898B43C856Fb0E51048B1b7bFBC9eDE"
  },
  "bodyType": "json",
  "method": "POST",
  "type": "http"
}

Promised output schema (from the provider)

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "input": {
      "additionalProperties": false,
      "properties": {
        "body": {
          "description": "Three shapes: {from, to, contacts?} scans the sender's recent Base USDC history; contacts-only {to, contacts} without from (aliases recipient/address + known_addresses/known) is offline lookalike vs contacts (no RPC); recipient-only {to} alone (alias address) scans that address's own recent USDC history for poisoning fingerprints.",
          "properties": {
            "chain": {
              "description": "Optional. Base only (base, eip155:8453, 8453). Any other chain returns 400 unsupported_chain and is not charged \u2014 Shield only scans Base USDC.",
              "type": [
                "string",
                "integer"
              ]
            },
            "contacts": {
              "description": "Optional: up to 50 trusted addresses / address book (aliases: known_addresses, known). With from: offline lookalike of contacts too. Without from: contacts-only mode (no RPC).",
              "items": {
                "pattern": "^0x[0-9a-fA-F]{40}$",
                "type": "string"
              },
              "maxItems": 50,
              "type": "array"
            },
            "from": {
              "description": "Sender address (aliases: sender, fromAddress). Omit for contacts-only or recipient-only mode.",
              "pattern": "^0x[0-9a-fA-F]{40}$",
              "type": "string"
            },
            "to": {
              "description": "Intended recipient (aliases: recipient, toAddress, address). Required in every shape.",
              "pattern": "^0x[0-9a-fA-F]{40}$",
              "type": "string"
            },
            "token": {
              "description": "Optional. USDC only (symbol USDC or Base USDC contract). Any other token (e.g. USDT) returns 400 unsupported_token and is not charged.",
              "type": "string"
            }
          },
          "required": [
            "to"
          ],
          "type": "object"
        },
        "bodyType": {
          "enum": [
            "json",
            "form-data",
            "text"
          ],
          "type": "string"
        },
        "method": {
          "enum": [
            "POST"
          ],
          "type": "string"
        },
        "type": {
          "const": "http",
          "type": "string"
        }
      },
      "required": [
        "type",
        "method",
        "bodyType",
        "body"
      ],
      "type": "object"
    },
    "output": {
      "properties": {
        "example": {
          "properties": {
            "chain": {
              "enum": [
                "base"
              ],
              "type": "string"
            },
            "contacts": {
              "description": "Only present when contacts were sent",
              "properties": {
                "checked": {
                  "type": "integer"
                },
                "inContacts": {
                  "type": "boolean"
                },
                "lookalikes": {
                  "items": {
                    "properties": {
                      "contact": {
                        "type": "string"
                      },
                      "prefixMatch": {
                        "type": "integer"
                      },
                      "suffixMatch": {
                        "type": "integer"
                      }
                    },
                    "type": "object"
                  },
                  "type": "array"
                }
              },
              "type": "object"
            },
            "coverage": {
              "properties": {
                "complete": {
                  "type": "boolean"
                },
                "coveragePct": {
                  "type": "number"
                },
                "lowCoverage": {
                  "description": "true when coveragePct < 10: almost nothing was scanned, so risk low does not mean safe (top reason explains; retry, pass contacts, or use /address/check/full)",
                  "type": "boolean"
                },
                "rpcCalls": {
                  "type": "integer"
                },
                "scannedFrom": {
                  "type": "integer"
                },
                "scannedTo": {
                  "type": "integer"
                },
                "transfersSeen": {
                  "type": "integer"
                },
                "windowBlocks": {
                  "type": "integer"
                }
              },
              "type": "object"
            },
            "ignoredFields": {
              "description": "Request fields Kertivo Shield did not use (they did not affect the answer); only present when there were any",
              "items": {
                "type": "string"
              },
              "type": "array"
            },
            "ignoredNote": {
              "type": "string"
            },
            "lookalikes": {
              "items": {
                "properties": {
                  "address": {
                    "type": "string"
                  },
                  "dustTransfers": {
                    "type": "integer"
                  },
                  "inbound": {
                    "type": "integer"
                  },
                  "lastBlock": {
                    "type": "integer"
                  },
                  "outbound": {
                    "type": "integer"
                  },
                  "pattern": {
                    "enum": [
                      "dust_or_zero_value",
                      "lookalike_counterparty"
                    ],
                    "type": "string"
                  },
                  "realOut": {
                    "type": "integer"
                  },
                  "sampleTx": {
 

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