What is email internationalization (i18n)?

Internationalization (i18n) is the technical foundation that enables your email system to support multiple languages and regions. It's the engineering work: ensuring your templates can handle any character set, your infrastructure can store and render multilingual content, and your systems can switch languages without breaking. Think of i18n as building a house with plumbing that can deliver water anywhere-localization is choosing which faucets to install where.

Key i18n requirements include UTF-8 encoding throughout your stack (from database to ESP to email headers), template architecture that separates content from structure, and systems that can store multiple versions of strings indexed by locale codes. Your templates need to accommodate text expansion (German runs longer than English) and text contraction (Chinese is often more compact). Right-to-left language support requires additional structural considerations in your HTML.

The \"18\" in i18n represents the 18 letters between 'i' and 'n' in \"internationalization\"-a fitting name for a concept that's all about handling complexity at scale. Getting i18n right upfront is dramatically easier than retrofitting it later. Internationalization is invisible infrastructure-your subscribers never see it, but they immediately notice when it's missing or broken.