translation/localization workflow for nodejs/express app
Why don't you just fork i18n-node and overwrite the read and write functions with your own persistence mechanism?
https://github.com/mashpie/i18n-node/blob/master/i18n.js#L235
It seems like you could easily persist the json data within a redis key instead of a json file with a few changes.
Another option to lingua might be http://i18next.com/node comes with backends in redis, mongodb or couchDb (and Filesystem of course!)