Leo Editor

Free plan APILinuxMacSelf-hostedWindows

What Leo Editor is

Leo Editor is a programmable editor, outliner, and knowledge base for organizing code, writing, and research in a flexible outline. Cloned nodes let one idea appear in several places while keeping its content synchronized. Users can shape workflows with Python scripts, commands, and plugins. Navigation includes expand and collapse, hoist and dehoist, promote and demote, clones, and clickable links; backlinks are also supported. Outlines can be exported to HTML, MORE, Markdown, Org mode, reStructuredText, and Vim outline formats. Leo connects to notebook, Python, and other programming workflows: @jupytext nodes let users edit notebook cells as outline nodes and write changes back to .ipynb files when saving. The leoBridge module gives Python host programs access to Leo source code, .leo file contents, and commanders. A WebSocket server accepts JSON requests to query or change outlines from clients in different programming languages. It requires a password and uses challenge-response authentication; TLS encryption is optional. Leo is free under the MIT license, which its maker says permits commercial use, modification, distribution, and resale. Installation requires Python 3.9 or later.

Who it suits

Leo suits people organizing code, writing, or research in outlines and those who want to extend workflows with Python or plugins. It is available for Windows, macOS, and Linux.

What it does well

Cloned nodes keep shared content synchronized.
Supports Markdown and backlinks.
Exports to six listed outline formats.
Jupyter notebook edits can write back to .ipynb.
MIT license permits commercial use.

What to know first

Installation requires Python 3.9 or later.
Asciidoctor integration requires separate software.
WebSocket TLS is optional.
The license disclaims warranties.

Limits

Leo Editor is free for commercial use, with no stated usage limits. The guide requires Python 3.9 or later; the Asciidoctor integration additionally requires Asciidoc3 or Asciidoctor available in PATH.

Plans

Plan	Billed and limits	Price
Leo Editor	Free for commercial use · no stated usage limits	Free

As leo-editor.github.io lists them, read 8 Oct 2026. The maker's own page has the final word.

Getting started

Visit the Leo Editor website.
Use the guide’s PyPI or GitHub installation route.
Make sure Python 3.9 or later is available.
Start organizing material in outlines and use scripts, commands, or plugins as needed.

Verdict

Leo Editor combines outlining and knowledge organization with scripting and integrations for notebook and programming workflows. Its Python requirement and optional setup components may matter when planning installation.

Questions

How much does Leo Editor cost?

The listed plan is free, and the pricing model is free.

Is Leo Editor open source?

Yes. The maker describes its license as MIT and permits use, modification, distribution, and resale, including commercial use.

Which platforms are listed?

The app lists Windows, macOS, and Linux. The broader platform list also includes API and self-hosted.

Can Leo work with Jupyter notebooks?

Yes. Its @jupytext nodes let users edit notebook cells as outline nodes and write changes back to .ipynb files when saving.

What does Leo require to install?

The guide requires Python 3.9 or later and describes installation from PyPI or GitHub.

Does Leo support Asciidoctor?

Its @adoc directive and adoc command require Asciidoc3 or Asciidoctor installed and available in PATH.

Facts from Leo Editor's own pages

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

Where Leo Editor stands on Freedom251

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