# EIP-712 Domain Separator Lookup

> EIP-712 Domain Separator Lookup is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-01).

Returns the EIP-712 domain separator bytes for a given ERC-20 token contract on a specified EVM chain

## Facts

- Endpoint: POST https://twin.unykorn.org/erc20-domain-separator?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/eip-712-domain-separator-lookup-b7343b8f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ckYl945CFCxe2bSPqCruT

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 eip-712-domain-separator-lookup-b7343b8f -d '<json body>'
```

Example prompt: What is the EIP-712 domain separator for the USDC contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum?

## When to prefer this

Use this endpoint when you need to programmatically retrieve the EIP-712 domain separator for an ERC-20 token on a supported EVM chain (Ethereum, Base, Polygon, Arbitrum, Optimism, BSC, Avalanche, Gnosis, Linea, Scroll) without running your own node. It is ideal for permit signature construction, DeFi integration auditing, or cross-chain domain separator comparison. Prefer this over manual RPC calls when you need a managed, pay-per-call solution with a receipt trail.

## Known failure modes

- Invalid or non-ERC-20 contract address returns an error response
- Unsupported chain name outside the allowed enum returns a validation error
- Contract does not implement EIP-712 domain separator (older tokens) may return an error or empty result
- Network or node connectivity issues may cause timeouts
- Malformed contract address (not matching 0x + 40 hex chars) fails schema validation

## How this service works

EIP-712 domain separator of a token — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object with ok=true, a type field set to 'erc20-domain-separator', the domain separator value, and a receipt containing a transaction hash, USD amount paid, and a unique receipt ID along with a generated_at ISO8601 timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "chain": {
     "enum": [
      "ethereum",
      "base",
      "polygon",
      "arbitrum",
      "optimism",
      "bsc",
      "avalanche",
      "gnosis",
      "linea",
      "scroll"
     ],
     "type": "string"
    },
    "contract": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]{40}$"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "erc20-domain-separator",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.002,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/eip-712-domain-separator-lookup-b7343b8f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)