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The library supports five different DNS resolvers to query DNS records. Each resolver has different runtime compatibility and use cases.

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Available resolvers

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cloudflare-dns

Uses Cloudflare’s DNS over HTTPS (DoH) API to query DNS records.
  • Endpoint: https://cloudflare-dns.com/dns-query
  • Format: JSON API
  • Requirements: Global fetch function
  • Runtime compatibility: Works in all JavaScript runtimes
Cloudflare DNS is a good choice for browser environments and serverless platforms like Cloudflare Workers.

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google-dns

Uses Google’s DNS over HTTPS (DoH) API to query DNS records.
  • Endpoint: https://dns.google/resolve
  • Format: JSON API
  • Requirements: Global fetch function
  • Runtime compatibility: Works in all JavaScript runtimes
Google DNS is the default resolver for most runtimes that aren’t Node.js or Cloudflare Workers.

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node-dns

Uses the Node.js built-in DNS module to query DNS records.
  • Module: node:dns
  • API: Uses native DNS resolution methods like resolveAny, resolve4, resolve6, etc.
  • Requirements: Node.js runtime
  • Runtime compatibility: Works only in Node.js
This is the default resolver when running in Node.js. It’s fast and doesn’t require external API calls.

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node-dig

Uses the dig command-line tool via Node.js child process.
  • Command: Spawns dig process with spawnSync
  • Output: Parses dig’s text output
  • Requirements: Node.js runtime and dig command installed on the system
  • Runtime compatibility: Works only in Node.js with dig available
Requires the dig command to be installed on the system. This resolver provides more detailed DNS information but has the overhead of spawning a child process.

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deno-dns

Intended for Deno runtime using Deno.resolveDns.
This resolver is not yet implemented. Using it will throw an error: “Deno DNS not yet implemented”.

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Runtime compatibility table

ResolverNode.jsBrowserCloudflare WorkersDenoBunNotes
cloudflare-dns✓✓✓✓✓Requires fetch
google-dns✓✓✓✓✓Requires fetch
node-dns✓✗✗✗✓Node.js only
node-dig✓✗✗✗✗Node.js + dig command
deno-dns✗✗✗✗✗Not yet implemented

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Specifying a resolver

You can specify which resolver to use when calling getDnsRecords or getAllDnsRecords: 
import { getDnsRecords, getAllDnsRecords } from '@layered/dns-records'

// Use Cloudflare DNS resolver
const txtRecords = await getDnsRecords('example.com', 'TXT', 'cloudflare-dns')

// Use Google DNS resolver for all records
const allRecords = await getAllDnsRecords('example.com', {
  resolver: 'google-dns'
})

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Automatic resolver selection

If you don’t specify a resolver, the library automatically selects the best one for your runtime: 
// Automatically uses:
// - 'node-dns' in Node.js
// - 'cloudflare-dns' in Cloudflare Workers
// - 'google-dns' in all other environments
const records = await getDnsRecords('example.com', 'A')
The selection logic from /home/daytona/workspace/source/src/get-dns-records.ts:5: 
function bestDnsResolverForThisRuntime(): string {
  if (globalThis.process?.release?.name === 'node') {
    return 'node-dns'
  } else if (globalThis.navigator?.userAgent === 'Cloudflare-Workers') {
    return 'cloudflare-dns'
  } else {
    return 'google-dns'
  }
}

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Implementation details

Both resolvers use DNS over HTTPS (DoH) APIs that return JSON responses. The library:
  1. Constructs a URL with the domain name and record type
  2. Makes a fetch request with appropriate headers
  3. Parses the JSON response
  4. Maps DNS type numbers (1 for A, 28 for AAAA, etc.) to type strings
  5. Normalizes record data by removing trailing dots from FQDNs
See /home/daytona/workspace/source/src/dns-resolvers.ts:33 and :61 for implementation.
The Node.js DNS module resolver uses native DNS resolution methods:
  • resolveAny() for all record types
  • resolve4() / resolve6() for A/AAAA records with TTL
  • resolveCname() for CNAME records
  • resolveMx() for MX records
  • resolveNs() for NS records
  • resolveSoa() for SOA records
  • resolveTxt() for TXT records
  • resolveCaa() for CAA records
See /home/daytona/workspace/source/src/dns-resolvers.ts:162 for implementation.
The dig resolver spawns a dig command as a child process with optimized flags:
  • +noall - Don’t display any text sections
  • +answer - Except the answer section
  • +cdflag - Skip DNSSEC checks for faster queries
It then parses the text output to extract DNS records.See /home/daytona/workspace/source/src/dns-resolvers.ts:96 for implementation.

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