# ENS Reverse Resolution

> ENS Reverse Resolution is a paid API for AI agents from chain.openverbs.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Reverse-resolves an Ethereum address to its primary ENS name by reading the reverse record live on Ethereum mainnet

## Facts

- Endpoint: POST https://chain.openverbs.com/v1/ens-reverse
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ens-reverse-resolution-b776ef51
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FuKCUChM-yz9Syk2ZXx6V

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-reverse-resolution-b776ef51 -d '<json body>'
```

Example prompt: What's the ENS name for the Ethereum address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045? Reverse-resolve it live on mainnet.

## When to prefer this

Use this endpoint when you need to resolve a raw 0x Ethereum address to a human-readable ENS name in real time. Prefer this over cached or off-chain lookups when freshness matters, since it reads live from Ethereum mainnet with automatic fallback. Ideal for identity enrichment, displaying friendly names in UIs, or verifying the ENS identity of a counterparty.

## Known failure modes

- Address has no primary ENS reverse record set — returns found:false
- Invalid address format (not a valid 0x hex address) — validation error
- Ethereum mainnet RPC unavailable — automatic fallback to secondary endpoint attempted; may return error if all fail
- Address is zero address or contract with no reverse record

## How this service works

Reverse-resolve an Ethereum address to its primary ENS name (the reverse record set by the owner), read live on Ethereum mainnet. Returns `found:false` when the address has no primary name set. Live reads with automatic endpoint fallback.

## Output

Returns a JSON object with the primary ENS name string if found (e.g. 'vitalik.eth'), or found:false when the address has no primary ENS reverse record set on Ethereum mainnet.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "20-byte hex address."
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ens-reverse-resolution-b776ef51/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from chain.openverbs.com](https://www.zero.xyz/host/chain.openverbs.com/llms.txt)