Regex Tester

Test, debug, and save regex patterns with real-time highlighting, group captures, and replace preview.

Test, debug, and save regex patterns with real-time highlighting, group captures, and replace preview. Regex Tester gives you a fast, in-browser regex testing tool right in your toolbar. No more switching to regex101.com — test patterns instantly without leaving your workflow. How it works: 1. Click the extension icon to open the regex tester. 2. Type a regex pattern and set flags (g, i, m, s, u). 3. Paste or type your test string — matches highlight in real time. 4. See all matches with group captures in the results panel. Features: - Real-time matching — matches highlight as you type the pattern or test string. - Flag toggles — click to enable g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode). - Group captures — see numbered capture groups for every match. - Replace mode — enter a replacement string and preview the result live. - Quick reference — 20 common regex patterns (email, URL, phone, IP, date, etc.) with one-click insert. - Save patterns — store frequently used patterns with labels for quick access. - Match count — see how many matches were found at a glance. - Copy results — copy matches or replaced text to clipboard. - Error display — friendly error messages for invalid regex syntax. - 100% local — no data leaves your browser. No accounts, no tracking, no servers. Privacy: Regex Tester does not collect, transmit, or share any data. Your saved patterns are stored locally using Chrome's built-in storage. No analytics, no telemetry, no third-party services.