# SendCheck Deep Crypto Address Verifier

> 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

## Facts

- Endpoint: POST https://api.pennyforge.org/deep
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sendcheck-deep-crypto-address-verifier-69cff103
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7dtkYdkPErivalUW_plQh

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability sendcheck-deep-crypto-address-verifier-69cff103 -d '<json body>'
```

Example prompt: Before I send 30 USDC, can you run a SendCheck deep scan on 0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D on Base — check the checksum, whether it's a contract or a regular wallet, and flag any network mismatch or USDC/USDT confusion?

## When to prefer this

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.

## Known failure modes

- 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

## 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.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "chain": {
   "enum": [
    "base",
    "ethereum",
    "arbitrum",
    "optimism",
    "polygon"
   ],
   "type": "string",
   "description": "Chain to scan (default: base)"
  },
  "address": {
   "type": "string",
   "description": "EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=…"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "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."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sendcheck-deep-crypto-address-verifier-69cff103/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.pennyforge.org](https://www.zero.xyz/host/api.pennyforge.org/llms.txt)