CSS Flexbox Playground

Visually design CSS Flexbox layouts. Adjust properties and copy the generated CSS instantly.

Container Properties

5 items

Live Preview

CSS Output


        

      

    

  

  







  
About the CSS Flexbox Playground

  

    The CSS Flexbox Playground is an interactive visualizer that lets you tweak every container-level flexbox property  -  direction, wrapping, justification, alignment, and gap  -  and see the effect on a live preview of up to 12 flex items in real time. The generated CSS updates instantly alongside the preview, so you can copy production-ready code the moment your layout looks right.
  

  
Common use cases

  





  
Frequently Asked Questions

  


    

      How does the Flexbox Playground generate and apply CSS in real time?
      
Each control in the playground is wired to a JavaScript event listener that reads the current value of all flexbox properties and assembles them into a CSS declaration block as a string. That string is injected into a <style> element scoped to the preview container, which the browser re-evaluates instantly, causing the flex items to reflow and paint without a page reload. The generated CSS output panel is updated in the same synchronous operation, ensuring the displayed code always matches the live preview exactly.

    


    

      What is the difference between justify-content and align-items?
      
justify-content distributes space along the main axis  -  for flex-direction: row, that is the horizontal axis, controlling how items are spaced left to right. align-items controls how items are positioned on the cross axis  -  the vertical axis in a row layout  -  determining whether they stretch to fill height, align to the top, center, or baseline. When flex-direction is set to column, the axes swap: justify-content controls vertical distribution and align-items controls horizontal alignment. The playground makes this axis relationship immediately visible by letting you toggle direction and observe both properties simultaneously.

    


    

      Does the generated CSS require any vendor prefixes?
      
No  -  the unprefixed display: flex syntax has been supported in Chrome since version 29, Firefox since 28, Safari since 9, and Edge since version 12, covering virtually 100% of browsers in active use today. The old display: -webkit-box and display: -ms-flexbox prefixed syntaxes were only necessary for browsers that went end-of-life before 2016. The tool outputs clean, modern CSS that works without modification in all current browsers and can be dropped directly into any production stylesheet.

    


    

      When should I use Flexbox versus CSS Grid?
      
Flexbox is a one-dimensional layout model  -  it excels at distributing items along a single axis, making it ideal for navigation bars, toolbars, button groups, and card rows where you want items to flow and wrap naturally. CSS Grid is two-dimensional and is better suited for page-level layouts, gallery grids, and any design where both rows and columns need explicit control. The two complement each other: a common pattern is using Grid for the overall page structure and Flexbox for the components within each grid area. This playground focuses exclusively on Flexbox properties; a separate Grid playground is available for two-dimensional layouts.

    


    

      How does this compare to CSS-Tricks' Flexbox guide or MDN documentation?
      
Reference guides like the CSS-Tricks Flexbox guide and MDN Web Docs are comprehensive written resources with static diagrams that explain every property in depth  -  invaluable for learning and looking up edge cases. This tool complements those references by providing a live sandbox where you can develop intuition through direct manipulation rather than reading about behavior. The instant feedback loop  -  especially for properties like flex-wrap, align-content, and gap  -  makes concepts click faster than diagrams alone, and the copy-ready output means you can move directly from experimentation to production code.