How This Regex Explanation Generator Works

This isn’t just another regex tester. It’s a real-time explanation engine that runs 100% in your browser — with zero backend, zero tracking, and zero data collection.

Client-Side Parsing Engine

Every character you type is parsed instantly using a custom TypeScript regex tokenizer. It breaks down:

  • Anchors (^, $)
  • Quantifiers (*, +, ?, {n,m})
  • Character classes ([a-z], \d)
  • Groups and alternations

Each token becomes a human-readable explanation — no external APIs, no RegExp constructor tricks.

Live Updates & Progress

Thanks to Svelte’s reactivity and async parsing with progress callbacks, even 10,000-character patterns are handled smoothly with a live progress bar.

Catastrophic Backtracking Detection

Dangerous patterns like (a+)+ or (.*)* are detected instantly and flagged with a red warning — preventing browser hangs before they happen.

Flavor-Aware Parsing

Switch between JavaScript, Python, PCRE, and Java — see how the same pattern behaves differently across engines.

Share via Link

Click “Share” → your regex is Base64-encoded in the URL. Open it anywhere — it auto-loads. No server. No storage. Pure privacy.

Open Source & Deployable

Built with SvelteKit + adapter-static. Deploy to GitHub Pages in one command. Fork it, customize it, own it.

FAQ

Why not use existing libraries?

Most are heavy, server-dependent, or don’t explain. This is lightweight and educational.

Can it handle very long regexes?

Yes — with smooth progress and no freezes.

Privacy-first. Developer-first. Forever free.