Regex Tester Common templates, live highlight, and replace preview — all in one page

Test Area
//
Click to expand: template notes
  • Email：Simplified email pattern.
  • URL (http/https)：Detects URLs starting with http or https (simplified).
  • IPv4：Four octets between 0–255.
  • Date YYYY-MM-DD：Simple date format (no leap/month checks).
  • HEX Color：Supports #RGB and #RRGGBB.
  • UUID v4：Standard UUID v4 format.
  • HTML Tag：Matches start/end tags (no multiline content).
  • Strong password (8+ with cases, digits, symbols)：At least 8 chars including upper/lower, digit and symbol.
Match Result
Matches：1
Elapsed ≈ 0.11 ms
Flags：g
Live Highlight Preview
(Enter regex and text to preview highlights)
Replace (supports $1, $2…)
Match Details
#IndexLengthMatch
100

About this Regex Tester

A browser-side tool to validate and debug regular expressions (regex). It features one-click templates, flag toggles, live highlighting with group borders, replace preview, and a detailed match table.

Typical use cases

  • Validate formats: Email, URL, IPv4, date, HEX colors, UUID.
  • Data cleanup: batch find/replace, extract groups.
  • Learning & debugging: visualize matches and capture groups.

Highlights

  • Common templates & flags g i m s u y d.
  • Replacement supports $1, $2… group references.
  • Everything runs locally in your browser; nothing is uploaded.

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