DNS Lookup API: How to Check DNS Records Programmatically

What Is a DNS Lookup API?

A DNS lookup API allows developers to programmatically query DNS records for any domain. Instead of manually using command-line tools like dig or nslookup, you can integrate DNS lookups directly into your applications via a simple REST API.

The Ops.Tools DNS Lookup API supports all standard record types including A, AAAA, MX, CNAME, TXT, NS, SOA, PTR, SRV, and CAA records. It returns structured JSON data with record values, TTL information, and metadata.

Supported DNS Record Types

Record Type	Description	Common Use Case
A	IPv4 address mapping	Server IP resolution
AAAA	IPv6 address mapping	Modern IP resolution
MX	Mail exchange servers	Email configuration
CNAME	Canonical name alias	Subdomain management
TXT	Text records	SPF, DKIM, DMARC
NS	Name servers	DNS infrastructure
SOA	Start of authority	Zone administration
PTR	Pointer (reverse DNS)	Email deliverability

Getting Started

Get Your API Key

Sign up for Ops.Tools and generate your API key from the dashboard. Professional plans start at $29/month for 6,000 API calls.

Make Your First DNS Lookup

curl -X GET "https://api.ops.tools/v1/dns/lookup" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d "domain=example.com&recordType=A"

Parse the JSON Response

{
  "domain": "example.com",
  "recordType": "A",
  "records": [
    {"value": "93.184.216.34", "ttl": 3600}
  ],
  "queryTime": "2026-03-17T10:30:00Z"
}

Implement TTL-Based Caching

Use the TTL values from API responses to implement client-side caching. This reduces API calls by 40-60% while ensuring data freshness.

Code Examples

Python

import requests

apiUrl = "https://api.ops.tools/v1/dns/lookup"
headers = {"Authorization": "Bearer YOUR_API_KEY"}

response = requests.get(apiUrl, headers=headers, params={
    "domain": "example.com",
    "recordType": "A"
})
data = response.json()

for record in data["records"]:
    print(f"Value: {record['value']} (TTL: {record['ttl']}s)")

Node.js

const response = await fetch(
  "https://api.ops.tools/v1/dns/lookup?domain=example.com&recordType=MX",
  { headers: { "Authorization": "Bearer YOUR_API_KEY" } }
);
const data = await response.json();

console.log(`Found ${data.records.length} MX records`);
data.records.forEach(r =>
  console.log(`  Priority ${r.priority}: ${r.value} (TTL: ${r.ttl}s)`)
);

Go

req, _ := http.NewRequest("GET",
    "https://api.ops.tools/v1/dns/lookup?domain=example.com&recordType=TXT",
    nil)
req.Header.Set("Authorization", "Bearer YOUR_API_KEY")

client := &http.Client{}
resp, _ := client.Do(req)
defer resp.Body.Close()

var result map[string]interface{}
json.NewDecoder(resp.Body).Decode(&result)
fmt.Printf("Records: %v\n", result["records"])

PHP

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,
    "https://api.ops.tools/v1/dns/lookup?domain=example.com&recordType=NS"
);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    "Authorization: Bearer YOUR_API_KEY"
]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$response = curl_exec($ch);
$data = json_decode($response, true);
echo "Name Servers: " . json_encode($data["records"]);

Caching Strategy

Record Type	Recommended Cache	Reason
A / AAAA	1-4 hours	IP changes are infrequent
MX	6-12 hours	Mail servers rarely change
TXT	1-6 hours	SPF/DKIM updates need fast propagation
NS	24-48 hours	DNS infrastructure changes are rare

Try the interactive DNS Lookup tool to see a live demonstration. For a deeper understanding of DNS record types, read our complete DNS records guide.

Frequently Asked Questions

Q: What is a DNS lookup API?

A DNS lookup API allows developers to programmatically query DNS records (A, AAAA, MX, CNAME, TXT, NS, SOA, PTR) for any domain. It returns structured JSON data instead of requiring manual DNS tool usage. The Ops.Tools API supports all standard record types with a single endpoint.

Q: How much does a DNS lookup API cost?

Ops.Tools DNS lookup API starts at $29/month for 6,000 lookups. The Growth plan at $99/month includes 32,500 lookups, and the Business plan at $249/month includes 145,000 lookups. Pay-as-you-go credits are also available for variable workloads.

Q: Can I query all DNS record types with one API?

Yes. The Ops.Tools DNS lookup API supports all standard DNS record types including A, AAAA, MX, CNAME, TXT, NS, SOA, PTR, SRV, and CAA records with a single API endpoint. Simply specify the recordType parameter in your request.

Q: What is DNS propagation?

DNS propagation is the process of distributing DNS record changes across all DNS servers worldwide. After making changes, it can take anywhere from a few minutes to 48 hours for all servers to reflect the new records, depending on TTL values. Use the DNS propagation checker to monitor changes globally.