# 402rpc ENS Resolver

> 402rpc ENS Resolver is a paid API for AI agents from 402rpc.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-15).

Resolves ENS names to Ethereum addresses (forward lookup) or Ethereum addresses to their verified primary ENS names (reverse lookup) using a full Ethereum mainnet node.

## Facts

- Endpoint: GET https://402rpc.com/v1/eth/ens?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/402rpc-ens-resolver-cd4d910a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Al_z46_wdFXkj3H4E_loC

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 402rpc-ens-resolver-cd4d910a
```

Example prompt: What Ethereum address does vitalik.eth resolve to? Use a full Ethereum mainnet node for the lookup.

## When to prefer this

Choose this endpoint when you need a trustworthy, full-node-backed ENS resolution without requiring an API key or account — ideal for agents that need to resolve payment addresses on-the-fly, label addresses in transaction history, or verify ENS identity ownership. Prefer over third-party ENS APIs when on-chain accuracy and decentralization matter, or when you want pay-per-call pricing without subscriptions.

## Known failure modes

- ENS name does not exist or has no resolver set — returns null or error
- Address has no primary ENS name set — returns empty reverse record
- Invalid ENS name format — rejected by pattern validation
- Invalid Ethereum address format — rejected by pattern validation
- Neither name nor address provided — missing required query parameter
- Temporary node connectivity issue — returns 5xx error
- ENS name exists but forward/reverse mismatch — reverse record not verified

## How this service works

Resolve ENS on Ethereum mainnet from a full node: name to address (e.g. vitalik.eth) or address to primary name (reverse record, verified forward). Use it to turn human-readable names into payment addresses and to label addresses. Give either name or address.

## Output

Returns either the resolved Ethereum address for a given ENS name (forward lookup) or the verified primary ENS name for a given address (reverse lookup, with forward-verification confirmed). Includes the canonical mapping between human-readable name and on-chain address.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "name": {
       "type": "string",
       "pattern": "^[^\\s]{3,255}\\.[a-z]{2,}$",
       "description": "ENS name, e.g. vitalik.eth."
      },
      "address": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$",
       "description": "Address for reverse lookup."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/402rpc-ens-resolver-cd4d910a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402rpc.com](https://www.zero.xyz/host/402rpc.com/llms.txt)