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Regex Debugger

Step-by-step breakdown of how a regex matches: capture groups, named groups, lookahead/lookbehind. Free online — runs locally, no upload.

//
$1year$2month$3day
2 matches
Match #1 · chars 9–19
Full Match

2026-09-07

Capture Groups

$1 (year)2026
$2 (month)09
$3 (day)07
Match #2 · chars 36–46
Full Match

2026-09-08

Capture Groups

$1 (year)2026
$2 (month)09
$3 (day)08

About Regex Debugger

Regex Debugger is a local-first networking & api utility on DevTooKit for everyday regex db tasks. Step-by-step breakdown of how a regex matches: capture groups, named groups, lookahead/lookbehind. DevTooKit keeps regex db work on-device and installable as a PWA for offline use. Pair it with neighboring tools instead of hopping across random websites.

What stays local: Requests, URLs, and payloads you inspect.

What you can do with Regex Debugger

  • Free online regex debugger — no account required
  • Step-by-step breakdown of how a regex matches: capture groups, named groups, lookahead/lookbehind
  • Runs locally in your browser (nothing uploaded for processing)
  • Works offline after installing the DevTooKit PWA

How to use Regex Debugger

  1. Open Regex Debugger. Go to the free Regex Debugger page on DevTooKit.
  2. Enter your input. Paste or type your regex db data — it stays in this browser tab.
  3. Run the tool. Use Regex Debugger to get results instantly with no server round-trip for processing.
  4. Copy and continue. Copy the output into your editor, PR, or API client as needed.

Privacy

What stays local: Requests, URLs, and payloads you inspect. DevTooKit is local-first — no signup wall, no server-side processing for this tool, and no watermark on results.

Related tools

FAQ — Regex Debugger

Privacy, offline use, and how this free online tool works.

Does Regex Debugger upload my data to a server?

No. Regex Debugger runs in your browser. Your input stays on this device and is not sent to DevTooKit for processing.

Is Regex Debugger free?

Yes — free, with no account and no paywall to use the core regex db workflow.

Does Regex Debugger send traffic to third-party servers?

Only when you explicitly run a request against a URL you choose. DevTooKit does not mirror your payloads for processing.

Can I use Regex Debugger offline?

Yes after the first visit. Install DevTooKit as a PWA and this tool keeps working without a network connection.

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