What are some alternatives?
When comparing Protranslate and GlotPress, you can also consider the following products
OneSky - Full Stack Localization Solution
Crowdin - Localize your product in a seamless way
Pootle - Multiple file formats.
Zanata - Homepage for Zanata translation software
Poedit - Poedit translations editor. The best way to translate apps and sites.
POEditor - The translation and localization management platform that's easy to use *and* affordable!