What is Localisation Testing?Localisation testing is the process of confirming that an application behaves as expected in each supported region. These regions could be broad — such as an EU-wide version of a site — or highly specific, like a custom landing page designed only for visitors from a single city. How does a website know where the user is?There are two main methods: IP Geolocation The website looks up the visitor’s IP address in a geolocation database to estimate their location. These databases are generally very accurate at the country level, and can sometimes narrow down to the city — though with less reliability. This method requires no input from the user. Browser Location API Modern browsers can provide precise location data using signals like GPS, nearby Wi-Fi networks, or cell towers. Unlike IP geolocation, this usually requires the user’s explicit permission before sharing. How do websites change their content?Websites typically use one of three approaches: Redirect to a country-specific TLD For example, a visitor from the UK navigating to example.com would be redirected to example.co.uk. Redirect to a region-specific path For example, a visitor from the UK landing on example.com would instead be taken to example.com/uk/. Serve location-specific content at the same URL In this case, the page at example.com shows different content depending on whether the visitor is in the UK or the USA — while keeping the same address. Is this how websites decide what language to use?Not always. While some websites rely on location to select a language, the better approach is to respect the user’s Accept-Language header. This allows people to choose their preferred language independent of their physical location. For example: A user in the UK may prefer to browse in French. A user in France may prefer to browse in English. What sort of content is localised?The specifics depend on the site, but common examples include: Displaying GDPR cookie banners to users in Europe, but not elsewhere. Showing region-specific content (e.g. Netflix only lists shows licensed in that region). Adjusting pricing to reflect local currencies and market expectations. What are the key steps in localisation testing? Identify the regions that have unique content You can’t test what you don’t know to look for. Start by mapping out which versions of the site exist (country, region, or city level) and what differs between them. Decide how to access region-specific versions of the site Common solutions include using proxy servers, VPNs, or test hooks built into the application that let you simulate being in a different location. Test from each location Verify that the actual behaviour matches the intended behaviour for each region. Be mindful of edge cases — for example, location-specific changes accidentally breaking other parts of the site.