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SendCheck Deep Crypto Address Verifier
x402
SendCheck Deep Crypto Address Verifier is a paid API for AI agents from api.pennyforge.org, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).
Verifies an EVM wallet address before sending crypto by checking EIP-55 checksum, network activity, contract vs EOA status, and native/USDC/USDT balances across multiple chains
Price / call$0.05
Success—
StatusUnknown
How this service works
Paste a wallet address and the chain you are about to send on. SendCheck checks the EIP-55 checksum, whether the address is actually active on that network, EOA or contract, native + USDC + USDT balances — and flags the USDT-instead-of-USDC trap. Every check is shareable: the link re-verifies live in the viewer's browser. Free, client-side, no account.
Output
Returns a JSON object with: checksum validity status and message, per-chain details (native/USDC/USDT balances, block number, reachability, contract flag, outgoing tx count), activity on other chains, and a verdict object containing a risk level (ok/warn/error), headline, reasons, and next-step recommendation — plus a shareable report string and a token mismatch field flagging USDT/USDC confusion.
Example use cases
Pre-send wallet safety check
“I'm about to send 500 USDC on Base to 0xAbCd1234abcd1234abcd1234abcd1234abcd1234 — can you deep scan it with SendCheck first to make sure the checksum is valid, the address is active on Base, and there's no token mix-up?”
Detecting wrong network before transfer
“This address 0x742d35Cc6634C0532925a3b844Bc454e4438f44e is supposed to be on Arbitrum, but I want to double-check — run SendCheck on it against Arbitrum and tell me if it looks more active on a different chain.”
Auditing contract vs EOA before DeFi interaction
“Can you use SendCheck to scan 0xdAC17F958D2ee523a2206206994597C13D831ec7 on Ethereum and tell me if it's a smart contract or a regular wallet, and what its native ETH and stablecoin balances look like?”
Technical details
Endpoint
POSThttps://api.pennyforge.org/deepWhen to prefer
Choose this endpoint when an agent or user is about to send crypto and needs pre-flight safety validation — specifically when the risk of wrong-network sends, checksum errors, or USDC/USDT confusion is present. It is the right choice over a generic blockchain explorer API when you want a human-readable verdict, multi-chain activity comparison, and stablecoin-specific mismatch detection all in one call.
Side effects
- Invalid address format (not 0x + 40 hex chars) returns an error before chain lookup
- Unsupported chain enum value returns a validation error
- RPC timeout or unreachable node may delay or fail the scan for a specific chain
- Address with zero history may return low-confidence activity signals
- Payment failure (x402) blocks the request if USDC is not provided
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| chain | string | Chain to scan (default: base) |
| address | string | EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=… |
Output
Schema · Response
{
"type": "json",
"example": {
"meta": {
"ms": 2140,
"service": "sendcheck",
"version": "1.8.1"
},
"chain": {
"name": "Base",
"usdc": "30.23",
"usdt": "0.00",
"block": 50804109,
"chain": 8453,
"native": "0.0026",
"reachable": true,
"usdcUnits": "30230079",
"usdtUnits": "0",
"isContract": false,
"outgoingTxs": 3
},
"others": [
{
"name": "Ethereum",
"usdc": "0.00",
"usdt": "0.00",
"chain": 1,
"native": "0.0",
"reachable": true,
"isContract": false,
"outgoingTxs": 12
}
],
"report": "SendCheck deep scan …",
"address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
"verdict": {
"gas": "0.00000039 ETH",
"next": "Confirm you truly mean Base before sending.",
"level": "warn",
"reasons": [
"…"
],
"headline": "Address is more active on Ethereum than on Base.",
"tokenMismatch": null
},
"checksum": {
"status": "valid",
"message": "Valid EIP-55 checksum address."
}
}
}Tags
x402
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