# DNS Reverse-IP Lookup API

> DNS Reverse-IP Lookup API is a paid API for AI agents from dns.payapi.market, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-17).

Resolves an IPv4 or IPv6 address to its PTR hostname and discovers other domains hosted on the same IP.

## Facts

- Endpoint: POST https://dns.payapi.market/dns/reverse?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-reverse-ip-lookup-api-622ccf9a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UC7btGmdtx2GJkkIWiaNO

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 dns-reverse-ip-lookup-api-622ccf9a -d '<json body>'
```

Example prompt: What domain name does the IP address 1.1.1.1 resolve to, and are there any other domains hosted on that same IP?

## When to prefer this

Choose this endpoint when you need to reverse-resolve an IP to its PTR hostname AND simultaneously discover other domains co-hosted on the same IP. It combines standard reverse-DNS with co-hosting enumeration in one call, making it ideal for security investigations, infrastructure reconnaissance, and network analysis workflows that need both pieces of data together.

## Known failure modes

- Invalid IP format returns a validation error
- HackerTarget daily rate limit (~100/day per IP) exhausted returns hackertarget_error field populated
- IPv6 addresses may have limited co-hosted domain data
- Private/reserved IP ranges may return no PTR or co-hosted domains
- Payment failure via x402 results in 402 response before query is executed

## How this service works

DNS records, WHOIS, SSL certificate, subdomain discovery, and reverse-IP lookup with x402 payments.

## Output

Returns the queried IP address, its primary PTR hostname record and any aliases, a list of other domains co-hosted on the same IP (sourced from HackerTarget), the count of co-hosted domains, and any error details from the HackerTarget lookup.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "ip": {
   "type": "string",
   "description": "IPv4 or IPv6 address to reverse-resolve, e.g. '1.1.1.1'."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ip": "1.1.1.1",
  "ptr": {
   "aliases": [],
   "primary": "one.one.one.one"
  },
  "other_domains": [
   "one.one.one.one",
   "1dot1dot1dot1.cloudflare-dns.com"
  ],
  "hackertarget_error": null,
  "other_domains_count": 2,
  "other_domains_source": "hackertarget.com (free, ~100/day per IP)"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/dns-reverse-ip-lookup-api-622ccf9a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dns.payapi.market](https://www.zero.xyz/host/dns.payapi.market/llms.txt)