To edit RESX files, you could use an advanced text editor like XML Editor, but note that simple text editors can corrupt your files. A better way is to use Localazy, crafted with translation file formats in mind.
Localazy makes it easy to manage your localization files in any format of your choice, and it does a lot of tasks for you automatically.
To open and edit RESX files using the Localazy interface, sign up for free, create a new translation project, and upload the RESX file using the file upload dialog or Localazy CLI tool. Then click on the File management tab to open your file.
You’ll be able to view and edit the file’s content using a standard interface.