What are some alternatives?
When comparing POEditor and Crowdin, you can also consider the following products
Transifex - Transifex makes it easy to collect, translate and deliver digital content, web and mobile apps in multiple languages. Localization for agile teams.
Poedit - Poedit translations editor. The best way to translate apps and sites.
Smartling - Website localization & translation
Lokalise - Localization tool for software developers. Web-based collaborative multi-platform editor, API/CLI, numerous plugins, iOS and Android SDK.
Pootle - Multiple file formats.
OneSky - Full Stack Localization Solution