# JustAName ENS Reverse Resolver

> JustAName ENS Reverse Resolver is a paid API for AI agents from api.justaname.id, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Resolves one or more Ethereum addresses into their ENS reverse records (human-readable names), with batch support up to 50 addresses and per-address chain scoping.

## Facts

- Endpoint: GET https://api.justaname.id/ens/v2/reverse
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-justaname-id-841a464a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_s8QrdGSRKjL7xRwg8JBds

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 api-justaname-id-841a464a
```

Example prompt: What ENS name is registered for the Ethereum address 0x1234567890abcdef1234567890abcdef12345678 on mainnet (chain ID 1)?

## When to prefer this

Use this endpoint when you need to display or identify wallet addresses by their human-readable ENS names, especially when handling up to 50 addresses at once or when you need per-address chain scoping via interop addresses. Prefer this over generic ENS resolvers when you need reliable batch reverse resolution with chain-level granularity.

## Known failure modes

- Address has no ENS reverse record set — returns empty or null name
- Invalid Ethereum address format — returns 400 error
- Batch exceeds 50 addresses — returns error or truncated results
- Unsupported chain ID — returns error or no result
- Network or provider downtime — returns 5xx error
- Rate limit exceeded — returns 429 error

## How this service works

Resolves an address into its ENS reverse record on a given chain, with batch support up to 50 addresses and per-address chain scoping via interop addresses.

## Output

Returns the ENS reverse record (human-readable name like 'vitalik.eth') for the provided Ethereum address(es), with per-address chain scoping when using interop addresses. Supports batch resolution of up to 50 addresses in a single call.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "address": [
    "0x1234567890123456789012345678901234567890"
   ],
   "coinType": "60"
  }
 }
}
```

## 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": {
    "body": {},
    "type": {
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE",
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "type": "string"
    },
    "queryParams": {
     "type": "object"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "enum": [
      "json",
      "text"
     ]
    },
    "format": {
     "type": "string"
    },
    "example": {}
   },
   "additionalProperties": false
  }
 },
 "additionalProperties": false
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "name": "vitalik.eth",
  "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "viaUniversalResolver": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-justaname-id-841a464a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.justaname.id](https://www.zero.xyz/host/api.justaname.id/llms.txt)