Our current solution to mange the translations involves a lot manual work (copy pasting) which makes it error prone. We were not able to find a easy solution to help us with this problem, how are you managing your localization, what tools are you using?
Thanks in advance.
Once your content is in a file, you'll be able to use a platform like Transifex (disclosure: I work there) to manage and automate your localization process. You'll be able to invite your translators, track the progress of work, and communicate directly with them. Once the translations are done, you can get the translated files via the web UI, API, or command-line tool and use them in your apps.
Most of our customers are software companies and use Transifex to make localization manageable even with daily or weekly releases. We have a case study of Eventbrite on our site at https://www.transifex.com/customers/casestudies/eventbrite/. Disqus also talked about how they use Transifex at a conference a few years back: http://confreaks.tv/videos/kodio_2014-continuous-translation....
Hope that helps!
There is desktop software as well as SaaS websites who offer to manage those files with online editors for you. Some have APIs that allow you to pull new translations (or whole files in the format of your choice). It makes it also easier when dealing with external translators or if you're in a hurry and want to pay somebody to translate just one string.
I used http://gengo.com/ in the past but they seem to have gone full enterprise now. https://www.transifex.com/ and https://poeditor.com/ look like good alternatives. I'm sure there are many others.
You can download and install the open source http://pootle.translatehouse.org/. That's what big open source projects like LibreOffice use.