Pattern

JavaScript RegExp syntax. Do not wrap with slashes.

Waiting

Test Text

Try one value per line for validation work.

Replacement string

Code flavor

Workbench

0 matches

Pattern Library

Validation starters. Confirm official formats before production enforcement.

Reference Notes

Useful syntax references for the implemented engine.

RegExp basics

JavaScript regex methods include exec, test, match, matchAll, replace, search and split.

MDN guide

Groups

Capture groups and named groups are surfaced in the Matches tab.

MDN groups

Unicode

Unicode property escapes need the unicode flag in many practical patterns.

MDN unicode

Lookbehind

Lookbehind assertions are useful but can behave differently from left-to-right matching intuition.

MDN lookbehind

Pattern review

Test regex against real positive and negative cases

Use match highlighting, captures, replacement output, code snippets, history, and copy actions to review a pattern before shipping it.

Local JavaScript regex

Sample text and patterns stay in your browser.

Methodology: run the JavaScript regex against sample text, inspect matches and captures, then review replacement and generated-code output.
Test realistic valid, invalid, empty, long, Unicode, and edge-case samples before enforcing a pattern in production.
Review flags, capture groups, anchors, replacement output, and catastrophic-backtracking risk.
Confirm official formats for phone numbers, IDs, tax numbers, payment references, or government codes before rejecting users.

Disclaimer: local JavaScript regex utility only, not an official validator or security guarantee.
Different languages and database engines can interpret regex syntax differently.
Do not paste sensitive logs or personal data into shared pattern examples.

Source/reference note: verify production formats against current API docs, regulator specs, or service-provider examples before deploying.

Test regex patterns against real African data shapes.