The Only Regex Generator for Edge Engineers
Cloudflare RE2 Protection
Generic AI tools output patterns with lookaheads (?=...) and lookbehinds. Cloudflare WAF strictly prohibits these to prevent ReDoS attacks. Select Cloudflare, and the AI guarantees RE2 safe constraints.
Regex Migration Engine
Migrating from Apache to NGINX, or NGINX to Cloudflare? Paste your legacy PCRE regex, select your new platform, and our engine will safely rewrite the exact logic without breaking features.
Frequently Asked Questions
How do I convert PCRE regex to Cloudflare RE2?
Select the "Regex Translation" mode in the toolbar. Paste your legacy Apache or NGINX PCRE regex — which may contain lookaheads or backreferences not supported by RE2 — then select Cloudflare WAF. The tool rewrites the pattern to be fully RE2-compliant.
How do I test my regular expression against sample strings?
Every pattern comes with AI-generated positive and negative test cases. These are automatically loaded into the Live Tester below the output. The tester runs safely inside a Web Worker to extract matches and Capture Groups instantly without locking your browser.
Can I export the generated regex to Python or JavaScript?
Yes. Use the Code Snippets tab to copy ready-to-use blocks for JavaScript (RegExp.test()), Python (re.search()), PHP (preg_match()), and Go (regexp.MatchString()). The code takes language-specific escaping into account.
What is the difference between PCRE and RE2 engines?
PCRE (Perl Compatible Regular Expressions) supports advanced processing features like lookaheads, lookbehinds, and backreferences. RE2 is a safer engine used by Cloudflare and NGINX that guarantees linear time matching to prevent ReDoS attacks. Migrating to RE2 requires rewriting unsupported syntactic sugar.
What is catastrophic backtracking and how is it prevented?
Catastrophic backtracking happens when a regex engine gets stuck computing millions of permutations for a failing string (known as a Regex Denial of Service or ReDoS). Our generator forces safe quantifiers when requested, and our live tester evaluates patterns inside an isolated 500ms timeout sandbox to ensure your tab never freezes.