Regex Find & Replace
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Simple find-and-replace can't handle patterns like phone numbers, dates in varying formats, or repeated whitespace, but this regex find and replace tool can, letting you match complex patterns and rewrite them using capture groups instantly. It's built for developers reformatting log files or config values, writers doing bulk find-and-replace across a manuscript, and data cleaners standardizing inconsistent formatting across a large text block. Enter your regular expression, a replacement pattern (including $1-style capture group references), and your source text, and see the result update live as you refine the pattern. Since matching and replacing happen entirely in your browser, none of your text is ever uploaded. Paste your text and pattern below to start replacing instantly.
Features
- Find and replace text using full regular expression syntax
- Support for capture groups in the replacement pattern
- Live preview of replacement results as you type
- Toggle common regex flags like case-insensitive and global matching
- Handles multi-line text and complex patterns
- One-click copy of the replaced output
- Highlights matches before replacement is applied
- Works on code, logs, or general text
Why use this regex find & replace?
- Performs pattern-based replacement instantly with live feedback
- Runs entirely client-side, keeping your text private
- Accurately supports capture groups and standard regex syntax
- Powerful yet approachable interface for regex beginners
- Free to use with no signup or restrictions
Frequently asked questions
How do I reference a capture group in the replacement text?
Use $1, $2, and so on to reference the first, second, and subsequent capture groups from your regex pattern in the replacement string.
What's the difference between this tool and a simple find-and-replace?
A simple find-and-replace matches exact literal text, while regex find and replace matches flexible patterns — like any sequence of digits or an optional set of characters — making it far more powerful for structured text.
Can I use common regex flags like case-insensitive matching?
Yes, the tool supports standard flags such as case-insensitive (i) and global (g) matching so you can control how broadly the pattern applies.
Is regex find and replace safe to use on sensitive text?
Yes, all matching and replacing happens locally in your browser using JavaScript's regex engine, so nothing is uploaded to a server.
Why isn't my regex pattern matching anything?
Common causes include unescaped special characters, incorrect flag settings, or a pattern that doesn't account for line breaks — reviewing the live match highlighting can help pinpoint the issue.
Can I preview matches before applying the replacement?
Yes, matches are typically highlighted in the source text before you confirm the replacement, letting you verify the pattern is correct.
From the blog
Regex for Beginners: Your First Ten Patterns
A regex tutorial for beginners built around ten patterns you will actually reuse — word search, validation, dates, phone numbers, URLs, and duplicate words.
Why Your Regex Is Slow: Catastrophic Backtracking
Catastrophic backtracking explained: why nested quantifiers like (a+)+ blow up exponentially, how to spot ReDoS patterns, and five ways to fix them for good.
Greedy vs Lazy Matching in Regex
Why your regex matches too much, how greedy and lazy quantifiers differ step by step, and the negated character class that usually beats both options.