How it works
How to use the Code Syntax Highlighter
Paste or open your input
Type, paste or drop a file into the left editor — or press Sample to try it.
Adjust the options
Use the options in the toolbar; the result updates as you type.
Copy or download the result
Copy the output or download it as a file.
About the Code Syntax Highlighter
Convert code into syntax-highlighted HTML with inline styles (or CSS classes) that you can paste into blogs, emails, documentation and CMS pages — no JavaScript highlighter needed on your site. 22 languages and 3 themes.
Built for developers
Why developers use it
Private by design
Runs 100% in your browser. Nothing you paste is uploaded, logged or stored on a server.
Instant results
Output updates as you type, with precise error locations when something is wrong.
Works offline
Once loaded, the tool keeps working without a connection. Install it as an app if you like.
Free, no sign-up
No accounts, no limits, no watermarks.
FAQ
Frequently asked questions
Does my code leave my computer?
No. Formatting, minifying and validation run entirely in your browser with open-source engines, so proprietary code stays private.
Is my data uploaded anywhere?
No. Everything runs locally in your browser — nothing you type, paste or open is sent to a server, logged or stored. The tool keeps working offline once the page has loaded.
Keep going
Related tools
- JSON Syntax HighlighterTurn JSON into highlighted HTML
- XML Syntax HighlighterTurn XML into highlighted HTML
- Online Code EditorEdit code in 40 languages in your browser
- Source Code ViewerView source code with syntax highlighting
- RSS Feed ViewerRead RSS and Atom feeds as articles
- Java EditorEdit Java code online
- Character to ASCII CodeGet the ASCII / Unicode code of each character
- QR Code GeneratorCreate QR codes for links, Wi-Fi, email and text