How is the data organized in Outline?

Outline is more than a note-taking app. It is your personal or professional knowledge base. You can use Outline to keep your simple day-to-day notes and to-dos,  but the real power of the app is in keeping the large amount of data from all areas of your life: 

• personal notes and hobby projects 📚
• work notes, drafts and meeting agendas 🔥
• school notes 🦄

Your data in Outline organized into four main levels:

Notebook is a topmost level data container. Think of Outline as a desk where you have several notebooks you currently work with. Data from all the notebooks is easily accessible for you in several clicks, and you can easily search though all opened notebooks.

When you do not need some of your notebooks anymore you can 'close' it. In this case, a notebook files will be stored where they are, but will not be accessible in Outline.

You can have many notebooks opened in Outline at the same time, so you do not need to open and close each of them when start and finish your work (like you do with the Word document), instead, you always keep the notebook open until you absolutely do not need it anymore (like when you finished the project).

Also, a notebook is an object you synchronize between your devices. You cannot synchronize an individual page or a section.

Having notebooks too big will cause the initial synchronization taking more time. So, for example, instead of having huge 'Work' notebook with many 'Projects' in it, it may be better to have separate notebooks for each project, like 'Work - Project Alfa', 'Work - Project Beta', etc.

Another good practice is to have 'Archive' (the data you do not use frequently) in a separate notebook. So you may have 'Work' and 'Work - Archive' or 'Personal' and 'Personal - Archive' and periodically move the data you do not need anymore into the Archive. That will allow you to keep your main notebook leaner, so it will sync faster.

Section is a logical and physical container for your pages. It has a name and keeps a list of pages, which, in turn, can be organized into hierarchy, as you can see it in this section. 

Section is a file, physically. All pages and all their edits including attached files and images are stored in the same file for a specific section. It would be a good practice to avoid too large section files in general (>100Mb) and split your pages into several sections. Practically, do not put too many pages into the same section. 

Page is..., well, a page with your data. It can contain text images files and more. 

You can use section groups when want to add a hierarchy of levels in your notebook. Think of it as a folder for a section. Section Groups can be nested.

How all this maps to a file system folder and files? Notebook and Section Group are folders, Section is a binary file with .one extension. All Pages are stored inside a corresponding section file.