TreeLine – stores almost any kind of information

Some would call TreeLine an Outliner, others would call it a PIM. Basically, it just stores almost any kind of information.

A tree structure makes it easy to keep things organized. And each node in the tree can contain several fields, forming a mini-database.

The output format for each node can be defined, and the output can be shown on the screen, printed, or exported to HTML.

Features include:


  • Stores almost any type of information, including plain text, rich text, HTML, numbers, dates, times, Boolean, URLs, etc.
  • The tree structure helps keep things organized.
  • Each node can have several fields that form a mini-database.
  • Several node types, with different sets of fields, can be included in one file.
  • The node format, including fields, output lines, formatting and tree-view icon, can be defined for each node type.


  • The left-hand view shows an indented, expandable list of titles.
  • The right-hand view can show one of three views – for showing output, editing node data and editing node titles.
  • The right-hand view is normally split to show data from the parent node and its children.
  • If multiple nodes are selected, the right-hand view shows all of their data.
  • The output view can be set to show indented output from all descendant nodes.
  • An upper breadcrumb view shows titles of the selected node’s ancestors; the titles can be clicked to select them in the tree.


  • Find commands can search node data for text matches or for more specific rules.
  • Filtering commands show only matching nodes in a flat left-hand view.
  • Previous and next selection commands toggle selections to quickly move between parts of the tree.


  • The dialog for data type configuration has several tabs to easily set all type, field and output parameters.
  • Each tree node can be set to a type format independently.
  • Formatting information can be copied from another TreeLine file.

File Handling

  • Undo and redo commands are available for all modifying operations.
  • TreeLine files use a JSON format, with options for automatically compressing or encrypting the files.
  • Document templates for new files are pre-formatted to cover basic needs.
  • The formatted output can be printed with parent/child lines, headers and footers.

File Import and Export

  • The data can be exported to single or multiple HTML files with optional navigation panes.
  • A live tree HTML export creates an interactive view with expandable nodes and a descendant output pane.
  • Plain text, tab-indented text and delimited table files can be imported and exported.
  • Files from older versions of TreeLine (2.x and 1.x) can be imported and exported.
  • Mozilla and XBEL format bookmark files can be imported and exported.
  • Generic XML files can be imported and exported, allowing TreeLine to function as a crude XML editor.
  • ODF text documents can be imported and exported as outlines.


  • Internal link fields select a linked node when clicked.
  • External link fields can be used to open URLs in web browsers.
  • Both internal and external links can be embedded into text fields.
  • Nodes that are duplicated by cloning show up as separate clickable paths in the upper breadcrumb view.

Data Manipulation

  • Nodes can be sorted by title or by predefined key fields.
  • Math fields can be defined that automatically calculate their contents based on numerical values in other nodes.
  • Numbering fields can be defined and automatically updated.
  • A node’s icon and output format can be changed conditionally based on its data.
  • Cloned nodes (the same nodes with multiple parents/locations) can be created using special paste commands or by automatically matching identical nodes.
  • Text data can be spell checked (requires an external program.
  • Data can be automatically re-arranged using categories from data fields.


  • There are many options for customizing both general and file-based attributes.
  • There are editors for keyboard shortcuts and toolbar commands.
  • Fonts used in the GUI, editors and output views can be customized.
  • The user interface is available in English, German and Spanish. Translations into other languages are TBD.

Website: treeline.bellz.org
Support: Documentation, GitHub Code Repository
Developer: Douglas W. Bell
License: GNU General Public License v2.0


TreeLine is written in Python. Learn Python with our recommended free books and free tutorials.

Return to Personal Information Managers

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