Generate CSS prefixes using pinned browser compatibility data.
Your input
Outputs are cleared when the input changes.
Result
Enter your data or use the example, then run the tool.
Worked example
The Safari 9 sample adds -webkit- prefixes to placeholder and user-select. Compare modern targets to see data-driven differences.
Method
PostCSS and pinned Autoprefixer transform text locally using bundled caniuse-lite. The exact data version and resolved query are shown. Input URLs remain CSS text and trigger no requests.
Limits
CSS ≤100,000 characters. Target presets are finite; no remote configs or popularity queries are loaded. Data is pinned, not live market share. IE Grid translation is disabled, and control comments may change plugin behavior. Warnings show locations for review; prefixes do not polyfill missing browser features.
All work stays in this browser. Each disposable worker is terminated after 2.5 seconds or cancellation. Inputs and processing logs are not sent to analytics.
Your inputs stay on this device. Only optional, consented page visits are measured. Input values, files, filenames and processing logs are not sent to Analytics.
When switching languages, text, settings and selected files are temporarily kept on this device. Transfers are removed after restoring; interrupted transfers are cleaned up on a later visit. Inputs and files are never uploaded.