What is Translation Coverage?

Translation coverage is the share of your translation keys that actually have a value in each target locale. If the source language defines a set of keys and German is missing some of them, German coverage is below complete, and users on that locale are seeing fallback text for the gap.

Coverage is the primary health metric of a localization pipeline because gaps are otherwise invisible: fallback locales keep the UI working, so nothing crashes and nobody files a bug. Measuring coverage per locale, and ideally per feature area, turns a silent quality problem into a number you can track and gate on.

Raw coverage also undercounts the problem: a key can be present but stale, translated against an older version of the source string. Mature workflows track both missing and outdated keys, and fail CI or block release when a locale falls below an agreed threshold. A TMS makes this cheap by computing the numbers continuously as keys are added and edited.