Own tool

Unclaimable

Active development. Preparing the first public NuGet release, 0.1.0.

Prevent unclaimable usernames.

Strict, fast username and identifier validation for .NET. Check a handle, slug, or account name before it can be claimed.

This is a library you add to a product, not a live web app. The default policy is intentionally strict — for most applications, configuration is optional. Private product names stay out of the global lists; those go in AdditionalReserved.

View on GitHub

Author

Perry3Dnl

License

MPL-2.0

Frameworks

.NET Standard 2.0+

Status

Active development

NuGet

0.1.0 coming soon

What it protects against

Reserved names

Blocks critical usernames like admin, support, and system, plus global brand and technology impersonation.

Separator tricks

Compact matching still catches variants such as admin_user, admin-user, and admin.user when those characters are allowed.

Leetspeak

Bounded substitutions such as adm1n, 4dm1n, and @dm1n.

Unicode lookalikes

Stops selected Cyrillic, Greek, and diacritic impersonation characters that look the same at a glance.

Fast and strict

No heavy dependencies. English by default; Dutch, German, or all three together. Length, numbers, and -/_ are rejected unless you opt out.

What it catches

• admin → reserved role
• supportive → support (strict partial match)
• john-doe → blocked character
• ordinary2 → numbers not allowed
• аpple → apple (Cyrillic lookalike)
• N1k3 → nike (when numbers are allowed)

Quick start

builder.Services.AddUnclaimable();

if (UnclaimableChecker.Default.IsClaimable(userName))
{
    // Passed the strict English default plus global datasets.
}

Packages

Unclaimable

netstandard2.0 dependency-free core and embedded datasets

Unclaimable.AspNetCore

net8.0 DI, live character policy, and [ClaimableUsername] validation

Not on NuGet yet. After 0.1.0 is published: dotnet add package Unclaimable --version 0.1.0

github.com/Perry3Dnl/Unclaimable Write-up on Projects