CSS Flex Gap Fallback Checker
Draft flex gap spacing with a margin fallback for older flexbox implementations.
What the CSS Flex Gap Fallback Checker does
Draft flex gap spacing with a margin fallback for older flexbox implementations. A horizontal button group can use gap normally and margin-left between siblings as a fallback Adjust the controls and the preview updates immediately, so you can dial in exactly what you want and copy the result straight into your project — no build step and no account.
One thing to keep in mind: Modern browsers support flex gap, but embedded webviews may still need testing.
Private and in your browser
Everything runs locally in your browser. Your input is never uploaded, so the tool stays fast and works offline, and the copy and download buttons always use the current result shown in the output panel.
Frequently Asked Questions
What does the CSS Flex Gap Fallback Checker do?
Draft flex gap spacing with a margin fallback for older flexbox implementations. A horizontal button group can use gap normally and margin-left between siblings as a fallback.
What should I keep in mind?
Modern browsers support flex gap, but embedded webviews may still need testing
Does it upload my input?
No. The CSS Flex Gap Fallback Checker runs entirely in your browser — your input is never uploaded, and it keeps working offline once the page has loaded.
Practical utilities for front-end design and implementation work.