Reverse DNS Lookup API

GET

Identify the hostnames behind any IPv4 or IPv6 address.

Reverse DNS Lookup resolves IPv4 and IPv6 addresses into their associated hostnames via PTR records. Pass any IP address to check if reverse records exist and receive all matching hostnames.

Try it — live request, no key required

Request

GETapi.apiverve.com/v1/reversednslookup?ip=8.8.8.8

Query parameters

ipstring

Verification

Format

No key required to try it. Get a key to use it in your app.

Example

{
  "status": "ok",
  "error": null,
  "data": {
    "ip": "8.8.8.8",
    "hostname": "dns.google",
    "ptr": [
      "dns.google"
    ],
    "found": true
  }
}

About the Reverse DNS Lookup API

Reverse DNS Lookup works by querying the PTR record for an IP address to find its associated hostname. This is useful for identifying servers, verifying email sender authenticity, and network troubleshooting.

What people use it for

Email Verification: Verify email sender authenticity by checking if the sending IP has a valid reverse DNS entry matching the sender domain
Server Identification: Identify what server or service is running on an IP address by looking up its hostname
Network Troubleshooting: Diagnose network issues by verifying that IP addresses resolve to expected hostnames
Security Analysis: Investigate suspicious IPs by discovering their associated hostnames and infrastructure

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON: Default REST response
XML: Markup format
YAML: Human-readable
CSV: Tabular export
GraphQL: Query language
MCP: For AI agents

View all integrations →

Other ways to use Reverse DNS Lookup

Same data, same APIVerve account, same credit balance — one key works on all of them.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.on VerveKit Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.on VerveSheets Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.on VerveContext

Questions.

Common questions about the Reverse DNS Lookup API.

Read the docs →

Does the lookup work for both IPv4 and IPv6 addresses?

Yes. You can pass standard IPv4 addresses or IPv6 addresses. Reverse DNS Lookup queries the PTR record for either format and returns the resolved hostnames.

What happens if an IP address does not have a PTR record?

The API sets the found field to false and provides a explanation in the message field. Your request completes cleanly without unhandled DNS timeouts, allowing your application to handle missing reverse records predictably.

Can an IP address return more than one hostname?

Yes. The primary match appears in the hostname field, and all resolved PTR records are returned in the ptr array so you can inspect every configured domain name.

How fresh are the reverse DNS records returned?

Every query resolves in real time directly from DNS. You receive current PTR records rather than stale cached data, which is essential when validating email senders or investigating live security alerts.

What would checking 10,000 IP addresses a month cost me?

That volume uses 100,000 credits, which fits well within the Starter plan allowance of 200,000 credits. At 10 credits per call, lookups work out to about $1.50 per 1,000 calls on Starter. The Free plan includes 20 calls per month for testing.

Can I use resolved hostnames inside my commercial security tool?

Yes, commercial use is fully permitted on any paid plan. You can use resolved hostnames inside your application for fraud detection, log enrichment, or server identification, provided you do not resell or redistribute the raw data as-is.

Request parameters — GET /v1/reversednslookup

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

Parameter	Type	Example	Description
`ip`Required	string	`8.8.8.8`	The IP address to lookup (IPv4 or IPv6) ip

Example request

1
2

curl "https://api.apiverve.com/v1/reversednslookup?ip=8.8.8.8" \
  -H "x-api-key: YOUR_API_KEY"

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Header	When	Value
`x-api-key`Required	Every request	Your API key. Header names are case-insensitive, so `X-API-Key` is the same header.
`Authorization`Alternate	Instead of the above	`Bearer <key>` — for clients that only expose bearer auth. Resolves to the same account and the same billing.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Response — GET /v1/reversednslookup

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "ip": "8.8.8.8",
    "hostname": "dns.google",
    "ptr": [
      "dns.google"
    ],
    "found": true
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`ip`	string	`"8.8.8.8"`	The IP address that was queried
`hostname`	string	`"dns.google"`	Hostname associated with the IP address
`ptr`	array	`[dns.google]`	All PTR hostnames resolved for the IP address
`found`	boolean	`true`	Whether a PTR record was found

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Header	What it carries
`x-api-remaining-credits`	Credits left in the current cycle
`x-api-credits-used`	Credits spent in the current cycle
`x-api-max-credits`	The allowance for the cycle
`x-api-version`	Version of the endpoint that answered

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter that has to change.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted here	A key restriction or an IP allow-list — never a bad key.
`429`	Rate limited, or out of credits	Read `error` to tell them apart, then back off or top up.

What a call costs — 10 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Plan	Per month	Credits	Reverse DNS Lookup calls	Per 1,000 calls
Free	Free	200	20	Free
Starter	$29.99	200,000	20,000	$1.50
Pro	$99.99	1,000,000	100,000	$1.00
Mega	$299.99	4,000,000	400,000	$0.75

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Compare all pricing tiers →

Call it from cURL — GET /v1/reversednslookup

No SDK to install — this is a plain HTTPS call to /v1/reversednslookup with your key in the x-api-key header. Swap in a real key and it runs as-is.

cURL

1
2

curl "https://api.apiverve.com/v1/reversednslookup" \
  -H "x-api-key: YOUR_API_KEY"

Resources

GitHubapiverve/reversednslookup-apiSource, issues and the examples this page is built from.ReferenceReverse DNS Lookup API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/reversednslookupnpm apiverve-reversednslookupPyPI APIVerve.API.ReverseDNSLookupNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Node.js — GET /v1/reversednslookup

Install the Node.js SDK, then call the Reverse DNS Lookup API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — npm

npm install @apiverve/reversednslookup

Node.js

const res = await fetch("https://api.apiverve.com/v1/reversednslookup", {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);

Resources

npm@apiverve/reversednslookupThe published Node.js client, versioned and signed.GitHubapiverve/reversednslookup-apiSource, issues and the examples this page is built from.ReferenceReverse DNS Lookup API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

apiverve-reversednslookupPyPI APIVerve.API.ReverseDNSLookupNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Python — GET /v1/reversednslookup

Install the Python SDK, then call the Reverse DNS Lookup API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — PyPI

pip install apiverve-reversednslookup

Python

import requests

res = requests.get(
    "https://api.apiverve.com/v1/reversednslookup",
    headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])

Resources

PyPIapiverve-reversednslookupThe published Python client, versioned and signed.GitHubapiverve/reversednslookup-apiSource, issues and the examples this page is built from.ReferenceReverse DNS Lookup API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/reversednslookupnpm APIVerve.API.ReverseDNSLookupNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from C# / .NET — GET /v1/reversednslookup

Install the C# / .NET SDK, then call the Reverse DNS Lookup API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — NuGet

dotnet add package APIVerve.API.ReverseDNSLookup

C# / .NET

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var json = await client.GetStringAsync("https://api.apiverve.com/v1/reversednslookup");
Console.WriteLine(json);

Resources

NuGetAPIVerve.API.ReverseDNSLookupThe published C# / .NET client, versioned and signed.GitHubapiverve/reversednslookup-apiSource, issues and the examples this page is built from.ReferenceReverse DNS Lookup API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/reversednslookupnpm apiverve-reversednslookupPyPI

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Go — GET /v1/reversednslookup

No SDK to install — this is a plain HTTPS call to /v1/reversednslookup with your key in the x-api-key header. Swap in a real key and it runs as-is.

req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/reversednslookup", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")

res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))

Resources

Also published for

@apiverve/reversednslookupnpm apiverve-reversednslookupPyPI APIVerve.API.ReverseDNSLookupNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from PHP — GET /v1/reversednslookup

No SDK to install — this is a plain HTTPS call to /v1/reversednslookup with your key in the x-api-key header. Swap in a real key and it runs as-is.

PHP

$ch = curl_init("https://api.apiverve.com/v1/reversednslookup");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);

$response = curl_exec($ch);
echo $response;

Resources

Also published for

@apiverve/reversednslookupnpm apiverve-reversednslookupPyPI APIVerve.API.ReverseDNSLookupNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Ruby — GET /v1/reversednslookup

No SDK to install — this is a plain HTTPS call to /v1/reversednslookup with your key in the x-api-key header. Swap in a real key and it runs as-is.

Ruby

require "net/http"

uri = URI("https://api.apiverve.com/v1/reversednslookup")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.body

Resources

Also published for

@apiverve/reversednslookupnpm apiverve-reversednslookupPyPI APIVerve.API.ReverseDNSLookupNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

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Reverse DNS Lookup API

Try it — live request, no key required

About the Reverse DNS Lookup API

What people use it for

Ways to call it

Other ways to use Reverse DNS Lookup

Questions.

Request parameters — GET /v1/reversednslookup

Required

Authentication

Response — GET /v1/reversednslookup

Response fields

Response headers

Errors

What a call costs — 10 credits per call

Call it from cURL — GET /v1/reversednslookup

Resources

Also published for

Call it from Node.js — GET /v1/reversednslookup

Resources

Also published for

Call it from Python — GET /v1/reversednslookup

Resources

Also published for

Call it from C# / .NET — GET /v1/reversednslookup

Resources

Also published for

Call it from Go — GET /v1/reversednslookup

Resources

Also published for

Call it from PHP — GET /v1/reversednslookup

Resources

Also published for

Call it from Ruby — GET /v1/reversednslookup

Resources

Also published for

Zero-code embed — one snippet, no backend

Changelog — Reverse DNS Lookup API

Domain Data

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