WhoisNET

A modern, structured WHOIS and RDAP client for .NET.

Supports all major TLDs (.com, .fr, .org, .de, .uk, .eu, .io, etc.) with strongly-typed results, RDAP-first with WHOIS fallback, async-first API, and DI support.

Features

• RDAP-first with WHOIS fallback — structured JSON when available, raw TCP when not
• Strongly-typed results — DomainInfo, RegistrarInfo, ContactInfo, NameServer, etc.
• Multi-TLD support — specialized parsers for .com, .fr, .de, .uk, .eu, .org, .io
• Async-first — all operations are async with CancellationToken support
• DI-friendly — IServiceCollection.AddWhoisNet() extension
• Standalone usage — works without DI via new DomainLookupClient()
• Built-in caching — in-memory cache with configurable TTL
• WHOIS referral handling — follows thin-to-thick referral chains
• Multi-targeting — netstandard2.0, net6.0, net8.0, net10.0
• Zero third-party dependencies — Microsoft packages only

Installation

dotnet add package DevWorker.WhoisNET

Quick Start

using DevWorker.WhoisNET;

using var client = new DomainLookupClient();

var result = await client.LookupAsync("google.com");
Console.WriteLine($"Registrar: {result.Registrar?.Name}");
Console.WriteLine($"Expires:   {result.ExpirationDate}");
Console.WriteLine($"NS:        {string.Join(", ", result.NameServers.Select(n => n.HostName))}");

Usage with DI

// In Startup / Program.cs
services.AddWhoisNet(options =>
{
    options.CacheDuration = TimeSpan.FromMinutes(30);
    options.RdapUserAgent = "MyApp/1.0";
});

// Inject IDomainLookupClient
public class MyService(IDomainLookupClient client)
{
    public async Task CheckDomain(string domain)
    {
        var info = await client.LookupAsync(domain);
        // ...
    }
}

Configuration

Option	Default	Description
CacheDuration	15 min	Default cache TTL
WhoisTimeout	10s	WHOIS TCP timeout
RdapTimeout	10s	RDAP HTTP timeout
RdapUserAgent	WhoisNET/1.0	User-Agent for RDAP
RdapBootstrapUrl	IANA URL	RDAP bootstrap endpoint
CustomServers	empty	Custom TLD-to-server mappings

Lookup Options

var result = await client.LookupAsync("example.fr", new LookupOptions
{
    Preference = LookupPreference.WhoisOnly,  // or RdapOnly, Auto (default)
    IncludeRawResponse = true,
    BypassCache = true,
    Timeout = TimeSpan.FromSeconds(20),
});

Check Domain Availability

bool available = await client.IsAvailableAsync("mynewdomain.com");

Raw Responses

// Raw WHOIS text
string whois = await client.GetRawWhoisAsync("example.com");

// Raw RDAP JSON
JsonDocument? rdap = await client.GetRawRdapAsync("example.com");

TLDs with Specialized Parsers

TLD	Registry	Parser
.com, .net	Verisign	ComWhoisParser
.org	PIR	OrgWhoisParser
.fr	AFNIC	FrWhoisParser
.de	DENIC	DeWhoisParser
.uk, .co.uk	Nominet	UkWhoisParser
.eu	EURid	EuWhoisParser
.io	NIC.io	IoWhoisParser

All other TLDs use the GenericWhoisParser (key-value format).

Authors

Nicolas ESTEBE

License

MIT