XLIFF

Definition

XLIFF (XML Localisation Interchange File Format) is an open, vendor-neutral file format maintained by OASIS. Its purpose is to give localizable content a standardised container so it can travel between different tools — a CMS, a CAT tool, a translation agency, and back — without each party needing to know anything about the source system's native format.

An XLIFF file wraps the source text in structured XML elements alongside the target translation (once completed), translator notes, metadata, and state information (new, translated, reviewed, final). Because it is XML, it is human-readable and can be diff'd in version control — an underrated advantage when content updates are frequent.

Two major versions are in active use: XLIFF 1.2 (2008, widely supported) and XLIFF 2.0 (2014, more modular and extensible). Many tools still default to 1.2 for compatibility, while newer platforms prefer 2.0 for its richer metadata capabilities.

Key Concepts

• Translation unit (<trans-unit>): The core building block of an XLIFF file. Each unit contains a source segment, an optional target translation, and optional notes or metadata.
• State attribute: Tracks the lifecycle of each translation unit: "new", "translated", "reviewed", or "final". Enables automated quality-gate workflows in pipelines.
• Inline elements: XLIFF uses <ph>, <g>, and <x> tags to wrap formatting codes (bold, links, placeholders) that must be preserved in the target but not translated.

Related Terms