DNSLib

A DNS client library for Dart with full support for UDP, TCP, and DNS-over-HTTPS (DoH) queries.

DNSLib enables direct DNS resolution from Dart applications without relying on platform-native libraries or system commands. It’s ideal for CLI tools, Flutter desktop apps, or network-sensitive environments where low-level DNS control is required.

Features

• Supports both IPv4 and IPv6.
• Works over UDP, TCP, and DoH.
• Fully asynchronous API.
• Minimal and dependency-free core.
• Built-in support for AXFR zone transfers.
• Compatible with Dart CLI, Flutter Desktop, and Flutter Web (DoH only).

Supported DNS record types

A, AAAA, AFSDB, APL, CAA, CDS, CERT, CNAME, DHCID, DLV, DNSKEY, EUI48, EUI64, HINFO, HIP, HTTPS, IPSECKEY, KEY, KX, LOC, MX, NAPTR, NS, NSEC, NSEC3PARAM, RP, SMIMEA, SOA, SRV, SSHFP, SVCB, TA, TXT, URI.

Installation

From the pub.dev repository using command dart pub add dnslib.

Short example

import 'package:dnslib/dnslib.dart';

// Create query
DNSClient // Returns a Future<List<DNSResponseRecord>>
    .query(
        domain: 'example.com',
        dnsRecordType: DNSRecordTypes.findByName('A'),
        dnsServer: DNSServer(host: '8.8.8.8'),
    )
    .then((records) {
        for (DNSResponseRecord record in records)
            print(record); // By default print in json format
    })
    .catchError((error) { // Catch any error here
        throw error;
    });

You can use a sync method:

final List<DNSResponseRecord> records = await DNSClient.query( // ...

You can see more examples in the example directory and execute this using:

dart run example/tcp.dart

DNSServer

The definition object and properties are:

const DNSServer({
    required this.host,
    this.port = 53, // Default port
    this.protocol = DNSProtocol.udp, // Default protocol
    this.path = '/dns-query', // Default path for DoH
    this.headers = const { // Default headers for DoH
        'Accept': 'application/dns-message',
        'Content-Type': 'application/dns-message',
        'Connection': 'close',
    },
});

Protocols supported by DNSProtocol are udp, tcp and doh.

DNSClient

The definition object and properties are:

class DNSClient {

    static Future<List<DNSResponseRecord>> query({
        required String domain,
        required DNSRecordType dnsRecordType,
        required DNSServer dnsServer,
        int timeout = 5000, // 5 seconds by default (in milliseconds)
    }) async { ...

Notes & Considerations

• DoH (DNS over HTTPS) uses port 443 and HTTPS protocol. You must set protocol: DNSProtocol.doh and port: 443 explicitly when using DoH.
• AXFR (zone transfer) is supported only over TCP. UDP and DoH do not support AXFR.
• All DNS queries use OPT records for extended responses and support for large payloads over TCP and UDP.

Contributions

This project is open source and under active development. Contributions, bug reports, and suggestions are welcome via GitHub.

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