Blazor WASM supports localization (i18n) — displaying text, dates, numbers, and currencies according to the user's culture and language preferences.

Setup

// Program.cs
builder.Services.AddLocalization();

// Set culture:
var culture = new CultureInfo("es-ES");
CultureInfo.DefaultThreadCurrentCulture = culture;
CultureInfo.DefaultThreadCurrentUICulture = culture;

Resource Files

• Resources/Pages/Index.resx — default English
• Resources/Pages/Index.es.resx — Spanish

Using IStringLocalizer

@inject IStringLocalizer<Index> L

<h1>@L["WelcomeTitle"]</h1>
<p>@L["WelcomeMessage", userName]</p>

Formatting Dates and Numbers

Once the culture is set, C# format strings automatically use the correct locale:

@price.ToString("C")  // $1,234.56 in en-US, €1.234,56 in de-DE
@date.ToString("D")   // Culture-appropriate long date

Runtime Culture Switching

Store the user's preference in localStorage and reload the page with the new culture set via JS interop.

Reference:

Wikipedia: Internationalization and Localization

https://en.wikipedia.org/wiki/Internationalization_and_localization