VS Code based editor
Syntax highlighting, autocompletion, bracket matching and automatic closing of HTML tags.
Free online code editor
Write and run HTML, CSS and JavaScript in your browser
No setup, no files. Write your code and see the result instantly in the preview next to it. Save your experiments, share them with a link or embed them on your site. No account needed to get started.
Open the editor
Start without signing up
- Free
- Live preview
- Works on mobile
What can you do?
You do not need a local setup to try a small idea, isolate a bug or build a piece of UI.
Live preview
The result updates as you type. Turn off auto run if you prefer to run the code yourself.
Flexible layout
Use the editor and preview side by side, stacked or in tabs, and drag the divider to resize the panels.
Console
See console.log output and JavaScript errors with line numbers right inside the editor.
AI assistance
Describe what you want and let AI write the code; you can also have it explain, review or suggest changes to your code (with a free account).
Share and embed
Share your pen with a link or add it to a blog post or documentation with the embed code. Download it as a ZIP.
Mobile friendly
On a phone you get a tabbed layout, a symbol key bar and one-tap preview for comfortable coding.
How does it work?
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Open the editor
A blank pen opens. Switch between the HTML, CSS and JS tabs to write your code.
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See the result
The preview updates as you type. The console shows errors and output instantly.
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Save and share
Save with your free account; keep it public, unlisted or private, and share it with a link or embed it.
Who is it for?
Learners
Write code, change it and see the result right away to understand how HTML and CSS work.
Developers
Try a component, an animation or a bug in isolation from the rest of your project.
Teachers
Share examples with a link so students can copy them and work on them.
Content creators
Embed working, interactive code examples in blog posts and documentation.
What is an online code editor for?
An online code editor lets you write and run HTML, CSS and JavaScript in the browser without installing anything. Your code runs inside a preview frame, so you see the result of every change immediately.
Tools like this are mostly used for small experiments: trying a CSS layout, checking how a JavaScript function behaves, or reproducing a bug in its smallest form to show someone else. Showing a bug in an isolated environment makes the problem much faster to understand when you ask for help.
When you save your pens you can showcase them publicly on the CodeBlanks Explore page, keep the ones you like in your own favorites lists, or share them so that only people with the link can see them.
Frequently asked questions
Is the code editor free?
Yes. Using the editor, writing and running code and saving your pens are free.
Do I need an account?
No. You can open the editor, write code and see the result without signing up. To save and share your pens and use the AI features, sign in with a free account.
Which languages are supported?
HTML, CSS and JavaScript that runs in the browser. Your code runs in a preview frame; server-side languages (PHP, Python, etc.) are not executed in this editor.
Can I use external libraries?
Yes. Add a CDN address with a script or link tag in the HTML section to use libraries and fonts.
Will my pens be public?
You decide. When saving you can choose public, unlisted (link only) or private.
Can I use it on my phone?
Yes. On mobile, HTML, CSS, JS and the preview are shown as tabs, and while the keyboard is open a key bar lets you insert symbols such as brackets, tags and tab with one tap.
Write your first experiment now
Open the editor, write your code and see the result instantly; create a free account whenever you want to save and share.
Open the editor