Globalization and Localization in ASP.NET Core

Modern applications are used by people from different countries, cultures, and languages.
ASP.NET Core provides built-in support for making your application culture- and language-aware.

What is Globalization?

Globalization is the process of designing an application to support multiple cultures.

It deals with:

Date & time formats
Number formats
Currency
Culture-specific rules

Example:

US Date → 12/31/2026
India Date → 31/12/2026
Currency → $100 vs ₹100

What is Localization?

Localization means adapting the application to a specific language or region.

It focuses on:

Translated text
Culture-specific resources
Language selection

Example:

English → “Welcome”
French → “Bienvenue”
Spanish → “Bienvenido”

Difference Between Globalization and Localization

Feature	Globalization	Localization
Purpose	Culture support	Language support
Scope	Formats & rules	Text & UI
Example	Date, currency	Messages, labels

Real-World Scenario

An e-commerce website supports:

English (US)
French (France)
Arabic (Saudi Arabia)

Users see:

Product prices in correct currency
Dates in local format
UI text in their language

Culture and Language in ASP.NET Core

ASP.NET Core uses:

Culture → formatting (en-US, fr-FR)
UICulture → UI language

Example culture codes:

en-US → English (United States)
fr-FR → French (France)
ar-SA → Arabic (Saudi Arabia)

Enable Localization in ASP.NET Core

Step 1: Add Localization Services

builder.Services.AddLocalization(options =>
{
    options.ResourcesPath = "Resources";
});

Step 2: Configure Supported Cultures

using Microsoft.AspNetCore.Localization;
using System.Globalization;

var supportedCultures = new[]
{
    new CultureInfo("en-US"),
    new CultureInfo("fr-FR"),
    new CultureInfo("ar-SA")
};

var localizationOptions = new RequestLocalizationOptions
{
    DefaultRequestCulture = new RequestCulture("en-US"),
    SupportedCultures = supportedCultures,
    SupportedUICultures = supportedCultures
};

app.UseRequestLocalization(localizationOptions);

How Culture is Selected

ASP.NET Core determines culture from:

Query string
Cookies
Request headers (Accept-Language)

Example Header

Accept-Language: fr-FR

Localization Using Resource Files (.resx)

Step 1: Create Resources Folder

Resources/
 └── Controllers.HomeController.en-US.resx
 └── Controllers.HomeController.fr-FR.resx

Step 2: Add Resource Keys

English (en-US)

Key	Value
WelcomeMessage	Welcome to our store

French (fr-FR)

Key	Value
WelcomeMessage	Bienvenue dans notre magasin

Using Localized Text in Controller

using Microsoft.Extensions.Localization;

[ApiController]
[Route("api/home")]
public class HomeController : ControllerBase
{
    private readonly IStringLocalizer<HomeController> _localizer;

    public HomeController(IStringLocalizer<HomeController> localizer)
    {
        _localizer = localizer;
    }

    [HttpGet]
    public IActionResult Get()
    {
        return Ok(_localizer["WelcomeMessage"]);
    }
}

Request Example (Real-Time)

English Request

GET /api/home
Accept-Language: en-US

Response

"Welcome to our store"

French Request

GET /api/home
Accept-Language: fr-FR

Response

"Bienvenue dans notre magasin"

Globalization Example (Date & Currency)

[HttpGet("date")]
public IActionResult GetDate()
{
    return Ok(new
    {
        Date = DateTime.Now.ToString("D"),
        Price = (1234.50).ToString("C")
    });
}

Output by Culture

Culture	Date	Currency
en-US	January 1, 2026	$1,234.50
fr-FR	1 janvier 2026	1 234,50 €
ar-SA	١ يناير ٢٠٢٦	ر.س 1,234.50

Using Query String for Culture

GET /api/home?culture=ar-SA

Interview-Ready Questions & Answers

Q1: What is globalization?

Globalization prepares an application to support multiple cultures and formats.

Q2: What is localization?

Localization adapts the application content to a specific language or region.

Q3: How does ASP.NET Core select culture?

Through query string, cookies, and request headers.

Q4: What are .resx files?

Resource files that store translated strings for different languages.

Summary

Concept	Purpose
Globalization	Culture formatting
Localization	Language translation
Resource files	Store translations
Request headers	Select language
ASP.NET Core	Built-in support