SendCheck: pre-send verification of any EVM address on one chain (EIP-55 checksum, wallet-
SendCheck: pre-send verification of any EVM address on one chain (EIP-55 checksum, wallet-vs-contract, outgoing activity, balances, verdict). POST {address, chain}
10000 (raw units)
price
2
calls / 30d
2
unique payers
2026-09-14
updated
Provider
sendcheck-x402.pennyforge.workers.dev · discovered, not yet claimed by its owner
Payment (x402 accepts[])
[
{
"scheme": "exact",
"network": "eip155:8453",
"payTo": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"amount": "10000",
"maxTimeoutSeconds": 60
}
]Output schema
{
"bazaar": {
"info": {
"input": {
"body": {
"address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
"chain": "base"
},
"bodyType": "json",
"method": "POST",
"type": "http"
},
"output": {
"example": {
"address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
"chain": {
"block": 50804109,
"chain": 8453,
"isContract": false,
"name": "Base",
"native": "0.0026",
"outgoingTxs": 3,
"reachable": true,
"usdc": "30.23",
"usdcUnits": "30230079",
"usdt": "0.00",
"usdtUnits": "0"
},
"checksum": {
"message": "Valid EIP-55 checksum address.",
"status": "valid"
},
"meta": {
"ms": 912,
"service": "sendcheck",
"version": "1.8.1"
},
"report": "SendCheck pre-send verification …",
"verdict": {
"gas": "0.00000039 ETH",
"headline": "Live wallet with recent activity.",
"level": "caution",
"next": "Verify the recipient out-of-band before sending.",
"reasons": [
"…"
],
"tokenMismatch": null
}
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"address": {
"description": "EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=…",
"type": "string"
},
"chain": {
"description": "Chain to scan (default: base)",
"enum": [
"base",
"ethereum",
"arbitrum",
"optimism",
"polygon"
],
"type": "string"
}
},
"required": [
"address"
],
"type": "object"
},
"bodyType": {
"enum": [
"json"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
},
"x-sendcheck-attestation": {
"info": {
"input": {
"body": {
"address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
"chain": "base"
},
"bodyType": "json",
"method": "POST",
"type": "http"
},
"output": {
"example": {
"jws": "<ES256 JWS compact: b64url(header).b64url(canonical-JSON payload).b64url(64-byte signature)>",
"key": {
"crv": "P-256",
"kid": "sendcheck-2026-09",
"kty": "EC",
"x": "<base64url P-256 X>",
"y": "<base64url P-256 Y>"
}
},
"type": "json"
}
},
"jws": "eyJhbGciOiJFUzI1NiIsImtpZCI6InNlbmRjaGVjay0yMDI2LTA5In0.eyJhc3NldCI6IjB4ODMzNTg5ZkNENmVEYjZFMDhmNGM3QzMyRDRmNzFiNTRiZEEwMjkxMyIsImV4cCI6MTgyMDM5MzQ3MCwiaWF0IjoxNzg4ODU3NDcwLCJuZXR3b3JrIjoiZWlwMTU1Ojg0NTMiLCJwYXlUbyI6IjB4OTUwNEE1OTM5QUI1YmUyQjJCMUY4YmVBN0Q3ZWJlQ2NkOTZjNDg1RCIsInJvdXRlcyI6W3sibWF4UHJpY2UiOiIwLjAxIiwicmVzb3VyY2UiOiIvY2hlY2sifSx7Im1heFByaWNlIjoiMC4wNSIsInJlc291cmNlIjoiL2RlZXAifV0sInNlcnZpY2UiOiJodHRwczovL2FwaS5wZW5ueWZvcmdlLm9yZyIsInYiOjF9.4aZJK5DYXZF3OHbKqFPTzWm8Ei9oSHBcjCkNawB0CAjLpTJHFG97Z8iicAWGms7cc9goKwGdCat_P0xeiOUkqQ",
"key": {
"alg": "ES256",
"crv": "P-256",
"kid": "sendcheck-2026-09",
"kty": "EC",
"use": "sig",
"x": "byHMSJi37KTtQRTkxSj1dNRUppDNKCMqj_W7dfC45Us",
"y": "mTV7jNFab5gU3P77chUHrdbnm3pegzrOjWdLXL3WRvs"
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"address": {
"description": "EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=…",
"type": "string"
},
"chain": {
"description": "Chain to scan (default: base)",
"enum": [
"base",
"ethereum",
"arbitrum",
"optimism",
"polygon"
],
"type": "string"
}
},
"required": [
"address"
],
"type": "object"
},
"bodyType": {
"enum": [
"json"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
}
}Use it
curl
curl "https://sendcheck-x402.pennyforge.workers.dev/check" # -> 402 Payment Required, accepts[] lists how to pay # retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid
JavaScript
const res = await fetch("https://sendcheck-x402.pennyforge.workers.dev/check");
if (res.status === 402) {
const { accepts } = await res.json();
// pay one of accepts[] via an x402 client, then retry with the payment header
}Python
import httpx
res = httpx.get("https://sendcheck-x402.pennyforge.workers.dev/check")
if res.status_code == 402:
accepts = res.json()["accepts"]
# pay one of accepts[] via an x402 client, then retry with the payment headerMachine-readable
Everything on this page is also available as clean JSON at /resources/7998.json, and this resource appears in /discovery/resources and /discovery/search.