Regex Debug

Debug regular expressions by listing matches and seeing which characters fall inside them. Step through regex matches with a per-character position map.

Introduction

Regex Debugger is a free, browser-based utility in our Regex Tools collection. Debug regular expressions by listing matches and seeing which characters fall inside them. Regex Debugger visualizes match positions to help troubleshoot patterns beyond a simple tester. Everything runs locally in your browser — inputs stay on your device, with no account or upload required. Highlights include match list.

Features

Match list
Position map
Flag toggles

How to use

1
Enter pattern and input.
2
Read the debug report.

Example

Words

Input

\b(\w+)\b

Output

match list + map

Benefits

Run Regex Debug entirely in the browser with no signup or installation.
Keep sensitive sample data private — processing never leaves your device.
Match list
Position map
Flag toggles
Pair it with Regex Tester and Regex Explainer when your workflow needs adjacent utilities.

FAQs

This maps match results, not a full NFA backtracking trace.

No.

Use Regex Tester for quick replace experiments.

Yes. Regex Debug on EverydayDevTools is free, with no account, watermarks, or usage caps for normal interactive use.

No. Regex Debug runs in your browser. Your input is processed locally and is not sent to EverydayDevTools servers.

Debug regular expressions by listing matches and seeing which characters fall inside them. It fits everyday regex tools tasks when you want a fast local utility instead of installing a CLI or opening a heavy IDE feature.

Core capabilities include: Match list; Position map; Flag toggles.

Developers often pair Regex Debug with Regex Tester, Regex Explainer, Regex Cheatsheet. Open Related tools on this page for quick links.