How to Perform and Automate Localization Testing

Anthony Enticknap
31 May 2024

4 min. read


You’ve just launched a website or an app, ready to welcome the influx of global visitors. And they come. Only to discover the lack of preferred payment options, overlapping text, and a missing language switcher.

This is a classic example of what can go wrong without proper localization testing.

Read on to discover how to perform localization testing for websites and apps. Our step-by-step guide will lead you through the testing process, showing you how to avoid common pitfalls and ensure a polished user experience.

What is localization testing?

Localization testing is a quality assurance process that verifies whether a website or an app functions correctly for a specific language and region. The tested areas are text, date and time formats, currencies, measurement units, UX and UI, legal and regulatory compliance, and functionality.

When should you perform localization testing?

Ideally, localization testing should be integrated early and throughout the development process, rather than being an afterthought before a product launch. Early integration helps you identify and resolve localization issues before they become embedded in the product.

But to be more specific, here are some key scenarios that require you to test localization:

  • Launching in a new market: This is the most obvious scenario, as you want to ensure your product is culturally appropriate and functions flawlessly for your new audience.
  • Updating existing content: After content translation or other updates, make sure all language versions are suitable for different regions.
  • Altering the UI/UX: After localizing your UI/UX, test it to ensure it remains user-friendly in the new region.
  • Complying with local regulations: Certain regions have specific regulations regarding data privacy, content, and accessibility, which localization testing helps you adhere to.

Skipping localization testing can lead to severe consequences. Not only could it result in a product that fails to connect with your target audience, but it could also lead to legal issues, reduced marketability, and ultimately, a tarnished brand reputation and lost revenue.

Checklist for localization testing

Before digging in, let's explore the core areas of localization QA to understand what needs testing and how to approach it.

Follow this checklist for each core area of localization testing:

Linguistic testing

  • Accuracy of translated content
  • Tone and style
  • Idiomatic expressions
  • Grammar
  • Spelling
  • Punctuation
  • Capitalization
  • Terminology usage
  • Untranslated text

Cultural testing

  • Appropriateness of translated content
  • Appropriateness of humor
  • Appropriateness of symbols
  • Appropriateness of colors
  • Appropriateness of images

Functionality and usability testing

  • Local currency formats
  • Local date and time formats
  • Local address and phone number formats
  • Local measurement units
  • Local numerical conventions
  • Local payment options
  • RTL languages
  • Error messages
  • Overlapping text
  • Truncated text
  • Fonts
  • Navigation
  • Language switcher
  • Loading speed
  • Forms
  • Buttons
  • Keyboard shortcuts
  • Scroll bar
  • Links

Compatibility testing

  • Local hardware compatibility

  • Local software compatibility

  • Local browser compatibility

  • Local plugins and extensions

Compliance testing

  • Compliance with local industry regulations
  • Compliance with local data protection laws
  • Compliance with local content and app rating
  • Compliance with local advertising regulations
  • Localization of legal and disclaimer texts

How to automate localization testing

While only human experts can assess legal compliance and cultural compliance, other areas of localization testing can be automated. Let’s see how to automate QA for your localized website or app.

Platforms, like Centus, have integrated localization testing tools, allowing you to minimize the manual effort involved in quality assurance. Using such tools, you can automatically identify the following issues in translated strings:

  • Spelling, grammar, and punctuation errors
  • Placeholder differences in the source and target text
  • Leading and trailing whitespaces
  • Bracket differences in the source and target text
  • Number differences in the source and target text
  • Email address differences in the source and target text
  • URL differences in the source and target text

Here’s how to automate localization testing for your app or website content:

  1. Sign up to Centus


  1. In the dashboard, click More


  1. In the dropdown menu, select Settings
  2. Click QA/Review and select the Warning option


  1. In the dashboard, double-click your project


  1. Review the detected errors
  2. Fix the issues or click Ignore to close the warnings

By performing automatic localization testing, you can detect easily avoidable yet embarrassing errors. After a round of automatic testing, arrange an editorial review to polish your content to perfection.

Parting thoughts

Test once and let it go? For better or worse, no. Just like localization itself, localization testing is an iterative process.

Test, update, and perfect.

How to perfect? Our expert guides on UI localization and Java localization are a good place to start.

Good luck!

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