CSS Flexbox Generator - Build Flex Layouts Visually Online
Create CSS Flexbox layouts with visual controls. Adjust direction, alignment, wrapping, and gap with live preview — generate clean CSS code.
Frequently Asked Questions
What is CSS Flexbox?
CSS Flexbox (Flexible Box Layout) is a CSS layout module that provides an efficient way to arrange, align, and distribute space among items in a container. Unlike traditional block/inline layouts, flexbox is direction-agnostic and works in one dimension (either a row or a column). It excels at distributing space and aligning content even when item sizes are dynamic or unknown, making it ideal for responsive designs, navigation bars, card layouts, and centering elements.
How do I use this Flexbox generator?
Set the container properties using the control panel: choose flex-direction, flex-wrap, justify-content, align-items, and gap values. Add or remove child items using the Add/Remove buttons (starts with 3 items by default). Click on any item in the preview to select it, then adjust its individual flex properties (grow, shrink, basis, order, align-self). Watch the live preview update instantly as you make changes. Optionally try a preset layout (Navbar, Card Grid, Sidebar, etc.) as a starting point. Copy the generated CSS and HTML code with the copy button.
Is my data secure? Does anything get sent to a server?
Yes, your data is completely secure. This tool runs entirely in your browser using client-side JavaScript. No layout configurations, CSS code, or any data is sent to any server. All code generation and preview rendering happens locally on your device, ensuring total privacy. You can safely use it for proprietary design work.
What is the difference between justify-content and align-items?
justify-content controls how items are distributed along the main axis (horizontal for flex-direction: row, vertical for flex-direction: column). It determines spacing between and around items. align-items controls how items are aligned along the cross axis (perpendicular to the main axis). For example, in a row layout, justify-content: center centers items horizontally, while align-items: center centers items vertically.
When should I use flex-wrap?
Use flex-wrap: wrap when you want items to flow onto multiple lines instead of being squeezed into a single line. This is essential for responsive card grids, tag lists, and any layout where items should naturally wrap to the next row when the container width is insufficient. Without wrapping (nowrap), all items are forced onto one line, which can cause overflow or items to shrink beyond their minimum size.
What is the gap property and why is it better than margins?
The gap property defines spacing between flex items without adding space on the outer edges of the container. Unlike margins, gap only creates space between items (not before the first or after the last), it does not cause margin collapse issues, and it works consistently regardless of flex-direction. You can set row-gap and column-gap independently for different horizontal and vertical spacing.
How do flex-grow, flex-shrink, and flex-basis work together?
These three properties control how items size themselves within the container. flex-basis sets the initial size of an item before remaining space is distributed (default: auto, meaning it uses the item's content size). flex-grow determines how much of the remaining free space an item should take (default: 0, meaning it does not grow). flex-shrink determines how much an item should shrink if the container is too small (default: 1, meaning it can shrink). For example, flex: 1 1 0 makes an item grow and shrink equally, taking an equal share of space.
Code Examples
// CSS Flexbox Generator - JavaScript
function generateFlexboxCSS(options = {}) {
const {
display = 'flex',
flexDirection = 'row',
flexWrap = 'nowrap',
justifyContent = 'flex-start',
alignItems = 'stretch',
alignContent = 'stretch',
rowGap = 0,
columnGap = 0,
} = options;
const rules = [`display: ${display}`];
if (flexDirection !== 'row') rules.push(`flex-direction: ${flexDirection}`);
if (flexWrap !== 'nowrap') rules.push(`flex-wrap: ${flexWrap}`);
if (justifyContent !== 'flex-start') rules.push(`justify-content: ${justifyContent}`);
if (alignItems !== 'stretch') rules.push(`align-items: ${alignItems}`);
if (alignContent !== 'stretch' && flexWrap !== 'nowrap') {
rules.push(`align-content: ${alignContent}`);
}
if (rowGap > 0 || columnGap > 0) {
if (rowGap === columnGap) {
rules.push(`gap: ${rowGap}px`);
} else {
rules.push(`gap: ${rowGap}px ${columnGap}px`);
}
}
return rules.map(r => `${r};`).join('\n');
}
function generateFlexItemCSS(options = {}) {
const {
flexGrow = 0,
flexShrink = 1,
flexBasis = 'auto',
order = 0,
alignSelf = 'auto',
} = options;
const rules = [];
if (flexGrow !== 0 || flexShrink !== 1 || flexBasis !== 'auto') {
rules.push(`flex: ${flexGrow} ${flexShrink} ${flexBasis}`);
}
if (order !== 0) rules.push(`order: ${order}`);
if (alignSelf !== 'auto') rules.push(`align-self: ${alignSelf}`);
return rules.map(r => `${r};`).join('\n');
}
// Usage
console.log(generateFlexboxCSS({
justifyContent: 'center',
alignItems: 'center',
rowGap: 16,
columnGap: 16,
}));
// display: flex;
// justify-content: center;
// align-items: center;
// gap: 16px;