RSyntaxTree is a graphical syntax tree generator for linguistic research.

Web App · Example Gallery · Documentation

RSyntaxTree provides a rich set of features for creating publication-quality syntax trees:

Use bracket notation to define tree structures:

[S [NP the cat] [VP [V sleeps]]]

Apply various text styles to node labels:

• Bold: **text**
• Italic: *text*
• Subscript: _text_
• Superscript: __text__
• Overline/Underline/Strikethrough: =text=, -text-, ~text~

Apply custom colors to individual nodes using @color: syntax:

[S [@red:NP the cat] [@blue:VP sleeps]]

Supports named colors (red, blue, green, etc.) and hex colors (@#FF5733:).

• Brackets: [#NP text] → draws brackets around the node
• Rectangle: [##NP text] → draws a rectangle around the node
• Triangle: [^NP the quick fox] → draws a triangle connector

Combine with colors: [#@red:NP text], [^@blue:VP phrase]

Connect nodes with lines or arrows:

[S [NP+1 text] [VP [V+>1 connects]]]

Generate trees in PNG, SVG, PDF, JPG, or GIF format.

A working web interface is available at https://yohasebe.com/rsyntaxtree.

You can also run RSyntaxTree's web interface on your local machine using Docker Desktop. See RSyntaxTree Web UI.

See RSyntaxTree Example Gallery for examples covering:

• Generative Grammar
• Combinatory Categorial Grammar
• Head-Driven Phrase Structure Grammar
• Cognitive Grammar
• Construction Grammar
• Pragmatics
• Phonology
• and more

Input text

[S
  [NP |R|<>SyntaxTree]
  [VP
    [V generates]
    [NP
      [Adj #\+multilingual\
            \+beautiful]
      [NP syntax\
          trees]
    ]
  ]
]

Output (PNG or SVG)

gem install rsyntaxtree

Important for macOS users: If you encounter build errors for native extensions (gobject-introspection, cairo-gobject, gio2), run the following commands before installing RSyntaxTree:

gem install gobject-introspection -- --with-ldflags="-Wl,-undefined,dynamic_lookup"
gem install cairo-gobject -- --with-ldflags="-Wl,-undefined,dynamic_lookup"
gem install gio2 -- --with-ldflags="-Wl,-undefined,dynamic_lookup"

Then install RSyntaxTree:

gem install rsyntaxtree

Alternatively, use the Docker image or the web interface.

Usage:
       1) rsyntaxtree [options] "[S [NP text] [VP here]]"
       2) rsyntaxtree [options] "(S (NP text) (VP here))"  # Penn Treebank format
       3) rsyntaxtree [options] "/path/to/text/file"
       4) echo "[S [NP text] [VP here]]" | rsyntaxtree [options]

Run rsyntaxtree -h for the full list of options.

• Bracket notation: [S [NP text] [VP here]]
• Penn Treebank format: (S (NP text) (VP here)) - automatically converted
• Standard input: echo "[S [NP text]]" | rsyntaxtree

RSyntaxTree supports configuration files (.rsyntaxtreerc) in YAML format. Place the file in your home directory or current working directory.

# ~/.rsyntaxtreerc
format: svg
color: modern
fontsize: 18

CLI options override config file settings.

For detailed documentation on syntax and markup:

• Documentation in English
• 日本語ドキュメント
• Example Gallery

Please use the following BibTeX entry when citing RSyntaxTree:

@misc{rsyntaxtree,
  author = {Yoichiro Hasebe},
  title = {RSyntaxTree: A graphical syntax tree image generator},
  url = {https://yohasebe.com/rsyntaxtree},
  year = {2026}
}

Yoichiro Hasebe (yohasebe@gmail.com)

RSyntaxTree is distributed under the MIT License.