Agent X Alpha

Regex Tester & Builder

Client-SideOffline ReadyNo login required

Write, test, and explain Regular Expressions in real-time against sample text with visual highlights.

Presets:
//
63 chars
7 Matches
Hello World, this is a Test String with Some Capitalized Words.
Match Details (7)
#1"Hello"Groups: ["H"]
idx: 0 (len: 5)
#2"World"Groups: ["W"]
idx: 6 (len: 5)
#3"Test"Groups: ["T"]
idx: 23 (len: 4)
#4"String"Groups: ["S"]
idx: 28 (len: 6)
#5"Some"Groups: ["S"]
idx: 40 (len: 4)
#6"Capitalized"Groups: ["C"]
idx: 45 (len: 11)
#7"Words"Groups: ["W"]
idx: 57 (len: 5)

Real-time Regex Engine

Test, evaluate, and debug Regular Expressions instantly with visual match highlighting and capture group breakdowns.

Visual Pattern Builder

Construct complex regex patterns visually without memorizing arcane syntax using configurable character rules.

Substitution & Code Generator

Simulate text replacements with capture group backreferences and export code snippets in JS, Python, Go, and PHP.

Frequently Asked Questions

Is Regex Tester & Builder free to use?
Yes, Regex Tester & Builder is 100% free to use on AgentXAlpha. There are no subscriptions, registration requirements, or hidden daily limits.
How does Regex Tester & Builder protect my privacy and data?
Regex Tester & Builder executes entirely client-side inside your browser memory using modern Web APIs. Your input and files are never uploaded to any remote server or third party.
Does Regex Tester & Builder work on mobile devices?
Yes, Regex Tester & Builder is fully responsive and optimized for touchscreens and desktop screens alike across iOS, Android, macOS, Windows, and Linux.
What are the main features of Regex Tester & Builder?
Write, test, and explain Regular Expressions in real-time against sample text with visual highlights. It is engineered for fast, zero-latency execution directly in your browser.
Recommended For You

More Dev Tools Utilities

View all Dev Tools tools
Dev Tools

Cron Generator & Expression Parser

Build, parse, and translate cron expressions visually. Features plain-English interpretation, next execution times (Local & UTC), and multi-platform snippets.

Client-SideLaunch
Dev Tools

JSON Formatter

Format, beautify, minify, and validate JSON instantly. Adjustable indentation with real-time syntax validation and error feedback.

Client-SideLaunch
Dev Tools

Markdown Preview

Write Markdown and see rendered HTML in real-time. Split-pane editor with copy Markdown/HTML.

Client-SideLaunch