Snap your prose into
clean, diff-friendly lines

A fast, format-aware semantic line break formatter for academic papers and collaborative writing.

View on GitHub Documentation

See it in action

One sentence, one line

Traditional wrapping hides changes in paragraph-wide diffs. Snapper breaks at sentence boundaries so every edit shows exactly what changed.

Before (traditional wrapping) We present a method for formatting prose documents with semantic line breaks, where each sentence occupies its own line. This approach dramatically reduces noise in version control diffs when multiple authors collaborate on a manuscript. Our tool handles LaTeX, Org-mode, Markdown, and plaintext with format-aware parsing that preserves structural elements.
After (snapper) We present a method for formatting prose documents with semantic line breaks, where each sentence occupies its own line. This approach dramatically reduces noise in version control diffs when multiple authors collaborate on a manuscript. Our tool handles LaTeX, Org-mode, Markdown, and plaintext with format-aware parsing that preserves structural elements.
Without snapper: change one word, diff shows entire paragraph --- a/paper.org +++ b/paper.org @@ -1,3 +1,3 @@ -We present a method for formatting prose documents with semantic line breaks, where each sentence occupies its own line. This approach dramatically reduces noise in version control diffs when multiple authors collaborate on a manuscript. Our tool handles LaTeX, Org-mode, Markdown, and plaintext with format-aware parsing that preserves structural elements. +We present a method for formatting prose documents with semantic line breaks, where each sentence occupies its own line. This approach significantly reduces noise in version control diffs when multiple authors collaborate on a manuscript. Our tool handles LaTeX, Org-mode, Markdown, and plaintext with format-aware parsing that preserves structural elements.
With snapper: same change, diff shows one line --- a/paper.org +++ b/paper.org @@ -1,3 +1,3 @@ We present a method for formatting prose documents with semantic line breaks, where each sentence occupies its own line. -This approach dramatically reduces noise in version control diffs when multiple authors collaborate on a manuscript. +This approach significantly reduces noise in version control diffs when multiple authors collaborate on a manuscript. Our tool handles LaTeX, Org-mode, Markdown, and plaintext with format-aware parsing that preserves structural elements.
snapper sdiff compares files at the sentence level. Whitespace reflow produces zero diff -- only actual content changes appear.
Same one-word change, but diffed at sentence level: $ snapper sdiff paper_v1.org paper_v2.org @@ -1,3 +1,3 @@ We present a method for formatting prose documents with semantic line breaks, where each sentence occupies its own line. -This approach dramatically reduces noise in version control diffs when multiple authors collaborate on a manuscript. +This approach significantly reduces noise in version control diffs when multiple authors collaborate on a manuscript. Our tool handles LaTeX, Org-mode, Markdown, and plaintext with format-aware parsing that preserves structural elements.
Paragraph reflow (rewrapping the same text) produces no diff at all: $ snapper sdiff wrapped_at_80.org semantic_breaks.org No sentence-level differences.

Features

Built for academic workflows

Everything you need to adopt semantic line breaks across your paper writing toolchain.

Format-aware parsing

Understands Org-mode, LaTeX, Markdown, RST, and plaintext natively. With pandoc backend: typst, asciidoc, docx, html, and more. Code blocks, math, tables pass through untouched.

Abbreviation-aware

Handles Dr., Fig., Eq., e.g., i.e., et al. and 80+ more. Add project-specific abbreviations via .snapperrc.toml.

Pre-commit hook

Ships with .pre-commit-hooks.yaml. Enforce semantic line breaks automatically on every commit across your team.

Editor integration

VS Code extension on the marketplace, LSP server for Neovim/Emacs/Helix, Apheleia, vim formatprg. Format on save in any editor.

Vale style package

Bundled vale rules flag lines with multiple sentences in your editor. Use --check for precise CI enforcement.

Git smudge/clean filter

Auto-format on commit, transparent to collaborators. Add to .gitattributes and formatting happens silently.

Neural sentence detection

Optional ML-based splitting via nnsplit for 9 languages. Use --neural --lang de for non-English text where rules fall short.

Skip regions with pragmas

Mark hand-formatted text with snapper:off / snapper:on comments. Poetry, aligned text, and ASCII art pass through untouched.

One-command setup

snapper init detects your formats and generates config, pre-commit hooks, gitattributes, and editor snippets.

Get started

Install in seconds

Cargo
# pre-built binary (fastest)
cargo binstall snapper-fmt
# or compile from source
cargo install snapper-fmt
Shell / Homebrew
# one-liner (Linux/macOS)
curl -LsSf https://github.com/TurtleTech-ehf/snapper/releases/latest/download/snapper-fmt-installer.sh | sh
# or Homebrew
brew install TurtleTech-ehf/tap/snapper-fmt
pip / Nix
# pip (with maturin wheels)
pip install snapper-fmt
# Nix
nix build github:TurtleTech-ehf/snapper
Pre-commit
# .pre-commit-config.yaml
- repo: https://github.com/TurtleTech-ehf/snapper
  rev: v0.3.1
  hooks:
    - id: snapper