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PayeeGuard
x402
PayeeGuard is a paid API for AI agents from payee.schemasure.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-14).
Pre-flight validates a Base/EVM payment destination address before sending, checking checksum, look-alike proximity, burn/precompile flags, and asset receivability.
Price / call$0.02
Success—
StatusUnknown
How this service works
Pre-flight a Base payment destination before you send. Verifies the EIP-55 checksum, measures distance from an address you expect — catching a mistyped digit and the shared prefix-and-suffix shape of a ground look-alike — flags the zero address, burn sinks and precompiles, refuses a token offered as its own payee, and reports whether the destination can receive the asset. Returns unknown rather than guessing when bytecode does not decide it. Not a judgement of the counterparty.
Output
Returns a structured validation report covering: EIP-55 checksum pass/fail, exact or case-only match against expected address, edit distance and look-alike (shared prefix/suffix) proximity score, flags for zero address, burn sinks, and precompiles, self-send detection when sender is provided, and an asset receivability assessment (native ETH or ERC-20). Returns 'unknown' rather than guessing when on-chain bytecode is ambiguous.
Example use cases
Clipboard hijack detection before transfer
“I'm about to send ETH to 0xdAC17F958D2ee523a2206206994597C13D831ec7 but I originally expected 0xdAC17F958D2ee523a2206206994597C13D831eC7 — can you check if those two differ in more than just casing and flag anything suspicious, like a shared-prefix look-alike attack?”
ERC-20 receivability check for a contract
“Check whether the address 0x0000000000000000000000000000000000000000 can receive USDC at contract 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 — I want to know if this is a burn address or zero address before I send anything.”
Self-send and token-as-payee sanity check
“I'm sending tokens from my wallet 0x742d35Cc6634C0532925a3b844Bc454e4438f44e and I want to pay to 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 using that same address as the asset — can you run a guard check to make sure I'm not accidentally sending a token to its own contract address?”
Technical details
Endpoint
POSThttps://payee.schemasure.com/v1/guard/payee?utm_source=zero.xyzWhen to prefer
Use PayeeGuard when an AI agent or automated payment flow is about to dispatch an on-chain transfer on Base and needs a lightweight pre-flight safety check: address checksum integrity, clipboard-hijack/look-alike proximity comparison, burn/precompile/zero-address filtering, and ERC-20 or native ETH receivability — all in a single call. Prefer this over generic address validators when the attacker model includes shared-prefix-and-suffix substitution attacks or when comparing a user-pasted address against an expected one. Not suitable for verifying counterparty identity, KYC, or off-chain payment rails.
Side effects
- Address fails regex pattern — must be a valid 0x-prefixed 40-hex-character string
- Normalizing address casing before submission destroys checksum evidence, producing false results
- Asset address provided as its own payee triggers self-referential flag rather than receivability answer
- Bytecode analysis inconclusive — endpoint returns 'unknown' for receivability rather than a definitive answer
- Network unavailability of Base RPC may cause timeouts
- Payment of $0.01 USDC via x402 required per call — missing payment header causes 402 rejection
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| from | string | The sender, when you have one. Enables the self-send check. |
| asset | string | "native" for ETH, or an ERC-20 contract address. Defaults to "native". The asset decides which receivability question is asked, and they have different answers. |
| address | string | The destination you are about to send to. Send it exactly as you hold it, casing included: the casing is the checksum, and normalising it before you ask destroys the evidence this endpoint checks. |
| expected_address | string | The address you believe the destination should be. Supplying it enables the comparison checks: exact match, case-only difference, small edit distance, and the shared prefix-and-suffix shape of a ground look-alike. |
Tags
x402
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