Fluid Topics (Commercial) - Online Platform for hosting DITA content.4Dpubs (Open Source - MIT) - Renders DITA directly in the browser with XSLT.Online Platforms and Publishing Solutions Translation-Package-Builder (Open Source - APL2) - oXygen XML plugin to generate translation packages from DITA.Contains a small translation management system. Fluenta DITA Translation Manager (Commercial) - Tool to convert DITA to XLIFF for sending it to a translator.DeltaXML (Commercial) - Tool to compare and merge DITA.oxygen-resources-convertor (Open Source - APL2) - oXygen XML plugin to convert resources from various formats (e.g.Migrate (Commercial) - Cloud service with automatic conversion of various formats, e.g.oxygen-git-plugin (Open Source - APL2) - oXygen XML plugin that provides a simple Git client.XML Documentation Add-on for Adobe Experience Manager (Commercial).RSI Content Solutions RSuite (Commercial).Empolis Smart Content Express (Commercial).Install the XML plugin and then add the catalog-dita.xml in the plugin settings to make DITA validation work.

jEdit (Open Source - GPL2) - Customizable text editor.

Eclipse (Open Source - EPL) - Can be enhanced to be used as a DITA editor, see Adding DITA to Eclipse by Ron Wheeler.Codex (Free for commercial and non-commercial use) - Simple DITA editor.It is also possible to setup a Git repository and keep that in your Google Drive or Microsoft OneDrive to collaborate with others. You can use FontoXML for free, when using it with Google Drive or Microsoft OneDrive.

Best xml editor open source