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SendCheck Crypto Address Verifier
x402
SendCheck Crypto Address Verifier is a paid API for AI agents from api.pennyforge.org, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).
Verifies an EVM wallet address before sending crypto: checks EIP-55 checksum, network activity, EOA vs contract status, native/USDC/USDT balances, and flags token confusion traps
Price / call$0.01
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 a verdict (level: ok/caution/warning), headline summary, array of reason strings, checksum validity status, whether the address is reachable on the specified chain, EOA vs contract flag, native token balance, USDC and USDT balances in human-readable and raw units, outgoing transaction count, current block number, estimated gas, and a next-step recommendation. Also includes a shareable report string.
Example use cases
Pre-send wallet safety check
“I'm about to send 500 USDC to 0xAbCd1234... on Ethereum — can you verify that address with SendCheck first? I want to make sure the checksum is valid, it's actually active on Ethereum, and it's not a contract.”
Catching wrong-network mistake
“My friend gave me their wallet address 0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D and said to send on Arbitrum, but I'm not sure if they meant Base — can you check it on both chains and tell me where it actually has activity?”
Detecting USDC vs USDT confusion
“I need to send stablecoins to 0x742d35Cc6634C0532925a3b844Bc454e4438f44e on Polygon — use SendCheck to see if there's any USDT/USDC mismatch risk I should know about before I hit send.”
Technical details
Endpoint
POSThttps://api.pennyforge.org/checkWhen to prefer
Use this endpoint when an AI agent or user is about to initiate a crypto transfer and needs a pre-flight safety check — particularly useful for flagging wrong-network sends, invalid checksums, contract addresses mistaken for EOAs, and USDC/USDT token confusion. Prefer this over generic blockchain explorers when you need a structured, machine-readable verdict with actionable guidance rather than raw block data.
Side effects
- Invalid address format returns checksum error with status 'invalid'
- Address not found on specified chain returns reachable: false with zero balances
- Unsupported chain value returns validation error
- Network RPC timeout may cause elevated latency or 5xx response
- Malformed 0x address (wrong length) rejected before chain lookup
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": 912,
"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
},
"report": "SendCheck pre-send verification …",
"address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
"verdict": {
"gas": "0.00000039 ETH",
"next": "Verify the recipient out-of-band before sending.",
"level": "caution",
"reasons": [
"…"
],
"headline": "Live wallet with recent activity.",
"tokenMismatch": null
},
"checksum": {
"status": "valid",
"message": "Valid EIP-55 checksum address."
}
}
}Tags
x402
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