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Leo Editor

leo-editor.github.io

Free plan WindowsmacOSLinuxAPISelf-hosted
Visit leo-editor.github.io
Spec score 8.0 #16 of 31 in Outliner Software

What it is

Leo Editor is a free, open-source programmable editor, outliner, and knowledge base for arranging code, writing, and research in flexible outlines. It runs on Windows, macOS, Linux, through an API, and as self-hosted software. Cloned nodes allow one idea to appear in several outline locations while remaining synchronized. Navigation includes expanding and collapsing, hoisting, promoting, clones, and clickable links, with backlinks available for related sections. Users can automate workflows with Python scripts, commands, and plugins. Outlines export to HTML, MORE, Markdown, Org mode, reStructuredText, and Vim outline formats. Jupyter integration lets @jupytext nodes represent notebook cells and save changes back to .ipynb files. The leoBridge module exposes Leo content to Python host programs. A WebSocket server accepts JSON queries and changes, using password challenge-response authentication; TLS is optional. Leo requires Python 3.9 or later and is distributed under the MIT license.

Spec sheet

Product
Leo describes itself as a programmable editor, outliner, and knowledge base for organizing code, writing, and research in a flexible outline.Read 8 Oct 2026 · leo-editor.github.io
Platforms
The installation guide explains how to install and run Leo on Windows, Linux, and MacOS.Read 8 Oct 2026 · leo-editor.github.io
Support
The installation guide directs users with installation problems to Leo’s help forum.Read 8 Oct 2026 · leo-editor.github.io
License
Leo is distributed under a license described by its maker as the MIT license and allows use, modification, distribution, and resale, including commercial use.Read 8 Oct 2026 · leo-editor.github.io
Asciidoctor integration
Leo’s @adoc directive and adoc command require Asciidoc3 or Asciidoctor installed and available in PATH.Read 8 Oct 2026 · leo-editor.github.io
Automation
Users can shape workflows with Python scripts, commands, and plugins.Read 8 Oct 2026 · leo-editor.github.io
Cloned nodes
Cloned nodes let the same idea appear in multiple places while keeping its content in sync.Read 8 Oct 2026 · leo-editor.github.io
Jupyter integration
Leo’s @jupytext nodes let users edit notebook cells as outline nodes and write changes back to .ipynb files when saving.Read 8 Oct 2026 · leo-editor.github.io
Plugins
The documentation says plugins in LeoPyRef.leo are part of the official distribution, and highlights a scripting plugin for creating script buttons.Read 8 Oct 2026 · leo-editor.github.io
Python embedding
The leoBridge module lets independent Python host programs access Leo source code, .leo file contents, and commanders.Read 8 Oct 2026 · leo-editor.github.io
Requirements
The guide requires Python 3.9 or later and describes installation from PyPI or GitHub.Read 8 Oct 2026 · leo-editor.github.io
Server authentication
The WebSocket server requires a password and uses a challenge-response process so the password itself is not sent over the connection.Read 8 Oct 2026 · leo-editor.github.io
Transport security
TLS encryption is optional for WebSocket connections and is enabled with certificate and key arguments.Read 8 Oct 2026 · leo-editor.github.io
Warranty
The license provides the software as is and disclaims warranties.Read 8 Oct 2026 · leo-editor.github.io
WebSocket server
Leo’s WebSocket server lets clients in different programming languages query or change outline contents using JSON requests and responses.Read 8 Oct 2026 · leo-editor.github.io

Plans and prices

Leo Editor Free Free for commercial use · no stated usage limits Read 8 Oct 2026 · leo-editor.github.io

Every Leo Editor plan and price →

Strong points and limits

Strong points

  • Free and open source
  • Cloned nodes keep repeated ideas synchronized
  • Python scripts, commands, and plugins
  • Exports to six listed formats
  • Runs on Windows, macOS, and Linux

Limits

  • Requires Python 3.9 or later
  • Asciidoctor features require separate installation
  • TLS for WebSockets is optional
  • No free trial is offered

Who it suits

It suits people organizing code, writing, or research in outlines who want scripting, plugins, cloning, and multiple export formats. It also fits Python users needing notebook, bridge, or WebSocket integration.

Verdict

Leo Editor combines outlining with programmable workflows, backlinks, cloning, and broad export options. Its integrations and self-hosted deployment suit technically oriented users who can meet its Python and optional tool requirements.

Where Specifiction places it

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