# ENS Name Resolution (Forward & Reverse) on Ethereum/Base/Optimism

> ENS Name Resolution (Forward & Reverse) on Ethereum/Base/Optimism is a paid API for AI agents from x402-audit.tatschluizguilherme.workers.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).

Resolves ENS names to Ethereum addresses (forward) or Ethereum addresses to ENS names (reverse) across Mainnet, Base, and Optimism via on-chain registry lookup

## Facts

- Endpoint: GET https://x402-audit.tatschluizguilherme.workers.dev/ens
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ens-name-resolution-forward-reverse-on-ethereum-base-optimism-818cf8d8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JFn85Vs8XYj1bXtC9yvKf

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 ens-name-resolution-forward-reverse-on-ethereum-base-optimism-818cf8d8
```

Example prompt: Before I send payment, can you resolve vitalik.eth to its Ethereum address on Mainnet so I can confirm who I'm paying?

## When to prefer this

Choose this endpoint when you need to perform ENS name resolution on Ethereum Mainnet, Base, or Optimism — particularly as a pre-payment identity verification step. It covers both forward and reverse resolution in a single API, supporting multiple EVM chains simultaneously, which is ideal for multi-chain wallet applications or payment agents that need to confirm counterparty identity before executing a transaction.

## Known failure modes

- ENS name not registered or expired — returns null or empty address
- Address has no reverse ENS record set — returns null name
- Unsupported chain specified — returns error indicating valid chains are Mainnet, Base, or Optimism
- Malformed ENS name or invalid Ethereum address input — returns validation error
- On-chain RPC node unavailability causing resolution timeout
- Name resolves to zero address (0x000...000) indicating unset or burned record

## How this service works

Pay-per-call on-chain API for AI agents and developers: wallet audits, token safety audits (honeypot detection), live gas prices, token prices, transaction receipts, balances, ENS resolution, block data, ERC-20 allowances, transaction simulation, swap quotes and multicall batches — all computed on-chain via public RPCs (no external market API). Pay per request in USDC on Base via the x402 exact scheme (EIP-3009 transferWithAuthorization). No API key, no signup, no subscription.

## Output

Returns the resolved Ethereum address (for forward lookups) or ENS name string (for reverse lookups), along with the chain on which the resolution was performed and any relevant registry metadata such as resolution status.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "name": "vitalik.eth",
  "type": "forward",
  "found": true,
  "address": "0xd8da6bf26964af9d7eed9e03e53415d37aa96045",
  "network": "mainnet",
  "resolver": "0x231b0ee14048e9dccd1d247744d114a4eb5e8e63",
  "blockNumber": 25684589,
  "requestedAt": "2026-08-05T00:40:00.000Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ens-name-resolution-forward-reverse-on-ethereum-base-optimism-818cf8d8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-audit.tatschluizguilherme.workers.dev](https://www.zero.xyz/host/x402-audit.tatschluizguilherme.workers.dev/llms.txt)