I've been building localised software my entire career, though for the first few years I wouldn't have called it that.
My first full-time software engineering job was building clinical software for the UK's National Health Service, the daily-driver software used by more than 100 GP practices and hospitals. When we expanded our customer base from England into Wales, everything we built had to work with the Welsh language as well as English. I naively thought it was a translation job - get every string into Welsh and you're done, surely?
My next job was at an event ticketing platform used by thousands of event organisers in the UK. I internationalised the main app and expanded payments from just British pounds to also support American dollars. Events happened in one timezone while the people buying tickets sat in another. When we launched in the US, American event organisers started contacting our support team. Our website, they told us, was full of typos (it wasn't).
After that, I moved to a world-class publishing company that runs more than 100 well-known brands and puts out hundreds of articles a day to hundreds of millions of readers worldwide, where I led the development of its internationalisation work that took its sites into 12 languages across more than 20 regions. Every region had its own readers, its own search traffic and its own idea of what the front page should show. Hundreds of articles a day is too many to translate by hand, so I also led work to streamline the editorial process for translating content in an ongoing basis, more than just translating the UI itself.
Today I build geocoding software. Most of the job is taking messy address and location data from different countries and turning it into something consistent that other developers can use. Every country does addresses its own way, and each one shows how differently the world works.
Throughout this I've also freelanced and consulted on many other projects in different areas, covering gaming, ecommerce and more, where localisation has always been a big meaningful part to help a business grow to a wider audience.
That's a lot of time to be getting localisation wrong, then less wrong, across games, healthcare, ticketing, publishing and geodata. This book is what I've learned along the way, so you can skip the parts where I got it wrong.
This book is a decade's worth of experience made bite-sized for you to benefit immediately.