Visually design CSS Flexbox layouts with instant preview. Adjust all flex container and item properties and export production-ready CSS.
Open CSS Flexbox Builder → free, no sign-inFlexbox is arguably the most useful layout tool in CSS, but explaining it to yourself — or debugging why something isn't centred the way you expected — still involves staring at properties like justify-content, align-items, and flex-wrap. The CSS Flexbox Builder gives you a live visual editor: adjust the flex container properties, add items, change their individual settings, and see the layout update in real time alongside the generated CSS.
Developers learning Flexbox, experienced developers who want to quickly prototype a layout without guessing at property combinations, and anyone who regularly needs to produce CSS layout code and wants to see the result before copying it.
No tutorials. No learning curve. Open it and get started.
No server uploads. Shows both the container CSS and the individual flex item properties — useful for layouts where items need different grow, shrink, or basis values.
Completely free. No trial period. No premium tier for basic functionality. No account required. Use it as often as you need.
One job, done well. CSS Flexbox Builder was built to solve a specific problem cleanly. No feature bloat, no ads, no distractions.
What is the difference between justify-content and align-items?
justify-content aligns items along the main axis (row direction). align-items aligns along the cross axis (perpendicular to rows).
What does flex-grow do?
flex-grow defines how much an item grows relative to others when extra space is available. 1 means it takes all available space equally with other grow:1 items.
What is flex-wrap?
flex-wrap controls whether items wrap to a new line when they run out of space in the container.
Can I use Flexbox for centering?
Yes — setting justify-content: center and align-items: center on a flex container centres its child elements both horizontally and vertically.
How does flex-basis work?
flex-basis sets the initial size of an item before flex-grow or flex-shrink is applied.
Free. Instant. No sign-in. Open it and get the job done.
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