What does that actually mean? Normally, on being un-picked, it implies quite user-specific choices. This is because different users work more heavily with different parts of the app. In addition, they work with different external apps which may themselves have limitations.
So, I’m guessing you want to export data files to a cloud service but it’s not yet clear which of Tinderbox’s near-400 attributes you need in [other apps] nor what such apps are. It’s also not clear if you are trying to move simple short sentences or complex, styled text.
Be aware that neither OPML nor Markdown are a single, stable standard. OPML-using apps almost always use some additional non-standard extensions. The Markdown environment is similar with a number of different ‘flavours’ build off the core. In either case, you need to check the import/export documentation of the other apps you wish to chose or ‘just’ exporting OPML/Markdown will likely not work as envisaged.
To help us help you, are you happy with the basics of Tinderbox export? In other words, how template files relate to exporting notes. If not, the OPML/MD work above will be harder, and a few moments to absorb the basics will help you with export work.
Also note that Tinderbox doesn’t, by design, ‘sync’ with any particular app(s). By ‘sync’ I mean an intention to have a single, similar, copy available to all users. Saving a TBX to a cloud location lets it be edited from different locations but only by one user at a time (if if that is you, but in different locations).
Tinderbox has powerful export. The challenge is normally figuring out the undocumented non-standard limitations of import into other apps. Importing also offers a number of other methods, but it is not a ‘sync’ and there is no merge method, lest that be assumed.
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