What is i18n?

i18n is short for “internationalization.” The word starts with an “i,” ends with an “n,” and has 18 letters in between, so it’s written as i‑18‑n. Internationalization is the process of designing and building software so that it can be easily adapted (or “localized”) for different languages, cultures, and regions without having to rewrite the code.

Let's break it down

  • Strings: All user‑visible text is moved out of the code into separate files (often called resource files).
  • Locale: A locale is a combination of language and region (e.g., en‑US, fr‑CA). The software reads the user’s locale to decide which resources to show.
  • Formatting: Dates, times, numbers, currencies, and plural forms are displayed according to local rules.
  • Encoding: Using Unicode (UTF‑8) ensures characters from any language are stored and displayed correctly.
  • Fallback: If a translation is missing, the system can fall back to a default language so the app still works.

Why does it matter?

  • Reach more users: People prefer products in their own language and cultural format.
  • Better user experience: Proper date, number, and currency formats reduce confusion.
  • Legal & compliance: Some countries require software to be available in the official language(s).
  • Competitive edge: Companies that support many locales can enter new markets faster than those that don’t.

Where is it used?

  • Websites and web applications (e.g., e‑commerce sites, social media platforms)
  • Mobile apps on iOS and Android
  • Desktop software (office suites, design tools)
  • Video games and interactive media
  • Embedded systems like ATMs, kiosks, and smart appliances
  • Cloud services and APIs that return locale‑specific data

Good things about it

  • Scalability: Add new languages by creating new resource files, not by changing core code.
  • Maintainability: All translatable text lives in one place, making updates easier.
  • User satisfaction: Users feel respected when software speaks their language and follows local conventions.
  • Market growth: Opens doors to global revenue streams.
  • Community support: Many frameworks (React, Angular, .NET, Java) have built‑in i18n tools and libraries.

Not-so-good things

  • Initial effort: Setting up i18n adds extra work at the start of a project.
  • Complexity: Handling plural rules, gender, right‑to‑left scripts, and locale‑specific layouts can be tricky.
  • Testing overhead: You need to test the app in multiple languages and regions to catch layout breaks or missing strings.
  • Translation costs: Professional translation and ongoing updates can be expensive.
  • Performance: Loading many language resources may increase bundle size or load time if not managed properly.