What syntax themes are available?

Eight themes are available: Atom One Dark, GitHub Light, Monokai, Visual Studio, Dracula, Nord, Tokyo Night, and GitHub Dark. Each theme uses a different colour palette optimised for code readability.

Code Syntax Highlighter

Paste code and get beautiful syntax-highlighted HTML instantly. Supports 24 languages, 8 themes, and exports a standalone HTML file.

Language

Theme

Lines

0 characters0 lines○ Loading hljs…

Input Code

Live Preview

Atom One Dark

Your highlighted code will appear here

Free Online Code Syntax Highlighter — Beautiful Code with One Click

Whether you are writing a technical blog post, building documentation, preparing a code tutorial, or creating a presentation that includes code samples, plain monospace text does not cut it. Code without syntax highlighting is harder to scan, harder to read, and less engaging for your audience. The OmniWebKit Code Syntax Highlighter solves this problem instantly and for free.

Paste any code snippet into the editor, choose your programming language from 24 supported options, and pick one of 8 professionally designed colour themes. The preview panel updates live as you type — no button required. When you are happy with the result, copy the raw highlighted code, copy the full standalone HTML file, or download it as a self-contained HTML document you can embed anywhere.

The tool is powered by Highlight.js, the most widely used open-source syntax highlighting library in the world. It uses the same tokeniser that powers thousands of documentation sites, GitHub Gists, and developer tools. That means the colour you see in the preview is accurate, reliable, and consistent with what developers expect.

All 8 Colour Themes Explained

Each theme is a carefully crafted colour palette created specifically for code readability. Here is a summary of all 8 themes and when to use each one.

Atom One Dark

The most popular dark theme. Based on the Atom editor. Uses a warm blue-grey background with violet keywords and green strings. Excellent for technical blogs and documentation.

GitHub Light

The exact theme used on GitHub for code display. White background, red keywords, blue strings. Familiar to most developers. Best for light-mode documentation and tutorials.

Monokai

One of the classic dark themes, originally created for Sublime Text. Deep olive-green background with pink keywords and gold strings. Iconic and immediately recognisable.

Visual Studio

The default theme from Microsoft Visual Studio IDE. White background, blue keywords, red strings, green comments. Perfect for corporate documentation and technical reports.

Dracula

A vibrant purple-tinted dark theme. Deep navy background with pink keywords and yellow strings. Popular for streaming, screenshots, and developer-facing content.

Nord

A cool, icy Arctic-inspired palette. Dark blue-grey background with muted blue keywords and green strings. Clean and minimalist, great for technical presentations.

Tokyo Night

A sophisticated deep blue-purple theme inspired by the neon cityscape of Tokyo at night. Lavender keywords, green strings. Perfect for creative content and developer blogs.

GitHub Dark

GitHub's official dark mode theme. Near-black background with warm red keywords and light blue strings. Consistent with GitHub's dark interface for developer-facing documentation.

How to Add Syntax-Highlighted Code to Your Website

The most practical output from this tool is the generated HTML/CSS section. This contains a complete standalone HTML document with all theme styles embedded as inline CSS. You can use it in several ways:

Embed in a webpage or CMS

Copy the HTML output, extract the relevant <pre><code>...</code></pre> block and the accompanying <style> tag, and paste both into your HTML page or CMS editor. The code will render with full colour highlighting without any external dependencies.

Use as an image replacement

Download the HTML file, open it in any browser, and take a screenshot. Many developers do this to create sharp, high-quality code images for slide decks, social media posts, or course materials where a screenshot looks cleaner than embedded HTML.

Use in email newsletters

Code in emails is tricky because email clients strip external stylesheets. Since this tool generates fully inline CSS, the styles are self-contained and will survive email rendering in most clients.

Share standalone previews

Download the HTML file and share it directly. Anyone who opens the file in a browser sees the highlighted code with your chosen theme — no Highlight.js CDN link required, everything is bundled.

Embed in Markdown via HTML blocks

Platforms like GitHub, Notion, and Confluence support raw HTML blocks. You can paste the generated <pre> block directly and the highlighted code will render natively inside your markdown document.

Frequently Asked Questions

Is this code syntax highlighter free?+

Yes, completely free with no account required. There are no usage limits. Paste as many code snippets as you need.

What languages does this tool support?+

The tool supports 24 languages: JavaScript, TypeScript, Python, Java, C++, C#, PHP, Ruby, Go, Rust, HTML, CSS, SQL, Bash, JSON, XML, YAML, Markdown, Swift, Kotlin, Scala, R, Perl, and Lua. Auto-detection is also available via Highlight.js.

What does the Download button produce?+

The Download button creates a self-contained HTML file with all theme CSS embedded inline. The file can be opened in any browser, shared via email, or embedded in any web page without external dependencies.

Why does the preview sometimes not highlight immediately?+

The tool loads Highlight.js from a CDN on first use. There may be a brief delay while the library loads. Once loaded, all subsequent highlights happen instantly. The status badge in the controls bar shows 'Ready' once Highlight.js is available.

Can I use the generated HTML in an email newsletter?+

Yes. The generated HTML uses only inline CSS styles from the theme data, not external stylesheets. This means the highlighted code will render correctly in most email clients, which typically strip external CSS links.

What is the difference between Copy HTML and Copy Code?+

Copy Code copies your original raw source code (what you typed in the left panel). Copy HTML copies the full highlighted HTML document including the theme CSS, ready to embed. Use Copy Code to share the source, and Copy HTML to share the styled output.

Is my code sent to any server?+

No. All highlighting happens entirely in your browser using the Highlight.js JavaScript library. Your code is never sent to any server. Everything runs locally in your browser tab.

What does the line numbers toggle do?+

It shows or hides line numbers in the input editor panel. This does not affect the generated HTML output — it only changes the display in the editor to help you navigate longer code snippets.