How do I swap two words with capture groups?

Capture each word and write them back in the new order: the pattern (\w+) (\w+) with the replacement $2 $1 turns hello world into world hello.

How do I use named groups in the replacement?

Name the group in the pattern with (? ...) and refer to it as $ . The pattern (? \d{4})-(? \d{2}) with the replacement $ /$ turns 2026-09 into 09/2026.

How do I insert a literal dollar sign?

Write $$. A $ before a digit, <, &, ` or ' can be read as a group or match reference, so write $$5 when you want the literal text $5.

Why does $0 not insert the whole match?

JavaScript has no $0 reference, so $0 stays in the output as literal text. Use $& to insert the whole match.

Regex replace with capture groups

Rearrange text by capturing parts of each match and writing them back in a new order. Refer to numbered groups as $1 and $2, named groups as $<name>, and the whole match as $&, and the result updates as you type. All processing runs in your browser.

Test string

REPLACE WITH

Result

Enter a pattern and test string above

MODE

Runs entirely in your browser

How it works

The tool uses the browser's native JavaScript RegExp engine. Patterns are compiled with new RegExp(pattern, flags) and run in a Web Worker that is stopped after 2 seconds, so a runaway pattern cannot freeze the page. Invalid patterns show an error message next to the pattern and never crash the page.

Processing runs in your browser

Both the pattern and the test string are processed entirely in your browser. Our servers are not involved at any point.

Related operations

For plain substring swaps without regex, try find and replace. To validate JSON patterns you are matching, use the JSON formatter. For decoding escape sequences in HTML attribute values, see HTML entities.

Frequently asked questions

How do I swap two words with capture groups?: Capture each word and write them back in the new order: the pattern (\w+) (\w+) with the replacement $2 $1 turns hello world into world hello.
How do I use named groups in the replacement?: Name the group in the pattern with (?<name>...) and refer to it as $<name>. The pattern (?<year>\d{4})-(?<month>\d{2}) with the replacement $<month>/$<year> turns 2026-09 into 09/2026.
How do I insert a literal dollar sign?: Write $$. A $ before a digit, <, &, ` or ' can be read as a group or match reference, so write $$5 when you want the literal text $5.
Why does $0 not insert the whole match?: JavaScript has no $0 reference, so $0 stays in the output as literal text. Use $& to insert the whole match.

Last reviewed September 30, 2026

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