Quickstart Guide
The ultimate playground for regular expressions
Skip the fluff. RegexNest is a stateful, client-side regex workbench designed for heavy lifters. This guide covers the essential syntax, keyboard shortcuts, and export workflows you need to become productive in under five minutes.
Core Concepts
RegexNest operates on a strict PCRE2-compatible engine with full support for named capture groups, recursive patterns, and variable-length lookbehinds. The interface is divided into three reactive panes: the Pattern Editor (with syntax highlighting), the Test String Input (supporting multi-line raw text), and the Match Inspector (visualizing overlapping matches and group indices).
When writing patterns, always define your flags globally in the settings bar rather than using inline modifiers (e.g., use the UI toggle for Case Insensitive instead of `(?i)`). This ensures your exported code remains clean and adheres to language-specific best practices.
Keyboard Shortcuts
Power users rely on the keyboard to iterate quickly. RegexNest binds critical actions to standard editor shortcuts to minimize context switching.
Test Pattern
Press Ctrl + Enter (Win/Linux) or Cmd + Enter (macOS) to immediately run the current pattern against the test string input.
Export Snippet
Hit Ctrl + Shift + E to open the export modal. This generates language-specific code using the currently selected target language.
Toggle Line Mode
Use Alt + L to switch between single-line and multi-line matching modes instantly, updating the match inspector in real-time.
Clear Input
Press Ctrl + / to clear the test string input area without losing your current regex pattern or settings.
Export to Code
The export engine translates your regex into production-ready snippets. It automatically handles escape sequences, flag conversions, and named group syntax specific to the target language.
Regex Crate
Generates code compatible with the regex crate. Named groups are automatically mapped to captures().name() calls, and unsupported features (like lookbehinds) trigger a compile-time warning.
RE2 Syntax
Exports to the standard regexp package. The exporter strips unsupported backreferences and converts PCRE-style flags to Go's inline modifiers to ensure strict RE2 compliance.
Native RegExp
Outputs the literal new RegExp() syntax. It correctly escapes forward slashes and maps global flags (g, i, m, s, u) to their JS equivalents.