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B20 Permit Data Reader (DOMAIN_SEPARATOR, Nonce, EIP-712)
x402
B20 Permit Data Reader (DOMAIN_SEPARATOR, Nonce, EIP-712) is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.03/call, status unknown (last checked 2026-09-14).
Returns ERC-2612 permit parameters for a B20 token — DOMAIN_SEPARATOR, owner nonce, and EIP-712 domain/type structs — so an agent can build a valid gasless approval signature.
Price / call$0.03
Success—
StatusUnknown
How this service works
🆕 Every B20 has ERC-2612 permit built in — approve a spender by signature instead of a transaction. Reads exactly what an agent needs to build a valid permit: the token's DOMAIN_SEPARATOR, the owner's current nonce (so the signed payload can't be rejected/replayed), and the EIP-712 domain/type struct. Read-only — signs nothing.
Output
Returns the token's DOMAIN_SEPARATOR, the owner's current nonce (preventing replay attacks), and the full EIP-712 domain and type structs needed to construct a valid ERC-2612 permit signature off-chain. No signing is performed by the endpoint.
Example use cases
Example prompt
“I need to build a gasless permit signature for the B20 token at address 0xAbC123... on Base — can you fetch the DOMAIN_SEPARATOR, EIP-712 type struct, and the current nonce for my wallet 0xDef456... so I can sign the permit off-chain?”
Technical details
Endpoint
GEThttps://402.com.tr/api/x402/b20-permitWhen to prefer
Use this endpoint when you need to construct an ERC-2612 gasless permit signature for a B20 token on Base, specifically when you need the DOMAIN_SEPARATOR and current owner nonce before signing. Prefer this over general-purpose RPC calls when you want a single structured response containing all three permit prerequisites (domain separator, nonce, EIP-712 structs) without writing custom contract ABI calls.
Side effects
- Invalid or non-B20 token address returns an error or empty data
- Token contract does not implement ERC-2612/permit — endpoint may return null or an error
- Owner wallet address malformed — query param validation error
- Token address not deployed on Base — contract call reverts
- RPC node unavailable — upstream timeout or 503
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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