Regex Testing, Visualization, and Pattern Debugging Tools

A searchable, localized cheat sheet for regular expression syntax — character classes, anchors, quantifiers, groups & references, lookarounds, escape sequences, and flags — with a built-in quick tester

Test regular expressions against text

Use AI to break down regular expressions into readable explanations

Step through how a regular expression matches a string position by position: visualize match attempts, partial successes, backtracks, and captures — a learning tool for understanding regex behavior, not just the final result

Render a regular expression as an SVG railroad (syntax) diagram showing literals, groups, alternations, and repetition, with capture-group numbering and flag explanations

Parse and display named capture groups from regex patterns

Match multiple regex patterns against text in one operation

Preview regex replacements in real-time with detailed diff highlights and statistics

Generate random strings that match a given regular expression pattern

Convert file matching patterns (Glob) to regular expressions

Detect error-prone and risky regex patterns, check for catastrophic backtracking, unanchored patterns, and provide rewrite suggestions

Compare performance of different regex patterns, identify bottlenecks, and detect degenerate cases

Scan one or more regex patterns for catastrophic backtracking risk, simulate evil inputs, and suggest safer rewrites