Juxta

Juxta — a fast, self-hostable, open-source side-by-side text & code diff tool. An open alternative to text-compare.com.

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Features

• Split & unified views — side-by-side or stacked diff rendering with smooth transitions
• Syntax highlighting — TypeScript/JS, HTML, CSS, JSON, and plain text with auto-detection
• Word & character inline diff — configurable granularity for intra-line changes
• Search with navigation — highlight matches and jump prev/next across both panes
• Whitespace / wrap / line-number toggles — per-session display controls
• Soft & high-contrast colour schemes — light and dark theme variants
• Per-side text transforms — lowercase, sort lines, remove excess whitespace, replace line breaks
• Swap & clear — one-click input management
• 4-format export — download diff as HTML, TXT, Markdown, or JSON
• Persisted preferences — all settings saved in localStorage, restored on reload
• Keyboard shortcuts — full Alt-key shortcut set; discoverable via Alt+K modal
• Sample loader — built-in example diffs to explore features immediately
• Light / dark theme — auto-follows system preference, manually overridable
• Analytics bar — live counts of additions, deletions, and changed lines
• Responsive layout — adapts gracefully from mobile to widescreen

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Self-Host Quickstart

Docker (recommended)

Pull the published image from GitHub Container Registry and run it:

docker run -p 3000:3000 ghcr.io/pranavp1507/juxta:latest

Or build it from source instead:

docker build -t juxta:latest .
docker run -p 3000:3000 juxta:latest

Then open http://localhost:3000.

Environment variables:

Variable	Default	Purpose
PORT	3000	HTTP port the server listens on
ORIGIN	(unset)	Public URL (required for CSRF protection in production, e.g. https://diff.example.com)

Docker Compose

Create a docker-compose.yml:

services:
  juxta:
    image: juxta:latest
    ports:
      - "3000:3000"
    environment:
      ORIGIN: https://diff.example.com
    restart: unless-stopped

Then:

docker compose up -d

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Local Development

Prerequisite: Bun ≥ 1.0

# Install dependencies
bun install

# Start dev server (hot reload, port 3000)
bun run dev

# Production build
bun run build

# Unit tests
bun test

# End-to-end tests (requires Playwright browsers installed)
bun run test:e2e

# Type-check
bun run check

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Tech Stack

Layer	Technology
Framework	SvelteKit + Svelte 5
Runtime / package manager	Bun
Styling	Tailwind CSS v4
Diff engine	Custom pure-TS LCS diff (no runtime deps)
Testing	Bun test + Playwright

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License

Juxta is licensed under the GNU Affero General Public License v3.0 (AGPL-3.0).

See LICENSE for the full text.

In short: you can use, modify, and self-host Juxta freely. If you distribute a modified version or run it as a network service, you must release your modifications under the same licence.