CSS Flexbox Generator
Stop guessing how `justify-content` works. Visually build beautiful, responsive flexbox layouts and instantly copy the production-ready CSS code.
How to Use
- Adjust the CSS dropdowns on the left panel to configure the container's behavior.
- Watch the Live Preview area instantly update to reflect exactly how the browser will render your layout.
- Use the + Add Box button to test how your layout behaves when the container is overflowing with children (this is perfect for testing the
flex-wrapproperty). - Once you have achieved your perfect alignment, click Copy CSS to grab the production-ready code.
Features
Visual Engine
Stop guessing how CSS behaves. See exactly how the browser's rendering engine aligns elements in real-time.
Gap Support
Includes support for the modern CSS gap property, eliminating the need for messy margin hacks.
Wrap Testing
Inject up to 20 child elements to test exactly how your grid breaks down on mobile devices.
Clean Output
The code generator strips out default values, giving you only the exact CSS required to build the layout.
Understanding Flexbox
CSS Flexbox (Flexible Box Layout) is the industry standard for creating responsive, 1-dimensional layouts. It completely replaced the horrible era of using HTML Tables, float: left, and clearfix hacks to align elements.
To use it, you apply display: flex; to a parent container. By doing this, all direct children inside that container become "flex items". You can then use two primary axes to align them:
- The Main Axis: Controlled by
justify-content. If your direction is set to "row" (the default), this aligns the items horizontally. - The Cross Axis: Controlled by
align-items. If your direction is a "row", this aligns the items vertically.
The Frontend Developer Suite
If you are building complex 2-dimensional layouts (like a magazine or dashboard), use our CSS Grid Generator. If you need to generate beautiful rounded corners for your child elements, try the CSS Border Radius Generator. To test how your layout looks with different cursors, use the CSS Cursor Viewer.
Frequently Asked Questions
Why isn't align-content doing anything?
The align-content property only works if your flex container has multiple lines of items. This means you must have flex-wrap: wrap turned on, and you must have enough child boxes to actually overflow the container into a second row. Try adding more boxes!
What is the difference between justify-content and align-items?
justify-content aligns items along the primary axis (horizontally, if you are in a row). align-items aligns items along the cross axis (vertically, if you are in a row).
Does this tool work offline?
Yes! The entire layout engine is powered by your local browser's native CSS rendering. You can disconnect from the internet and the generator will still function perfectly.
Is it free?
Yes, 100% free with no limits.