Input a regex pattern, instantly generate runnable code in 6 languages
Zero Dependencies Β· Works Offlineπ Enter Regex Pattern
π Test Text
π» Generated Code
What is the Regex Code Generator?
The Regex Code Generator is an online tool designed for developers that automatically converts input regex patterns into runnable code in JavaScript, Python, Go, Java, PHP, and Rust. Skip the hassle of looking up each language's regex API β get complete match, replace, and group extraction code snippets instantly, ready to copy into your project.
Core Features
- 6-Language Code Generation: Supports JavaScript, Python, Go, Java, PHP, and Rust with idiomatic code for each language
- 3 Operation Modes: Match test, replace, and group extraction covering common regex use cases
- Real-time Syntax Validation: Instant regex syntax checking with precise error location, supports g/i/m/s flags
- Inline Test Preview: Enter test text to see match results with highlighted positions and group contents
- One-click Copy & Download: Copy single language code or download all languages as files, with history tracking
How to Use
1. Enter your regex pattern in the input field, e.g., email validation [\w.+-]+@[\w-]+\.[\w.]+. The tool validates syntax automatically.
2. Select flags (g global / i case-insensitive / m multiline / s dotAll) and operation mode (match / replace / extract). For replace mode, enter the replacement text.
3. Enter or paste test text to see real-time match preview with highlighted results.
4. Click language tabs to switch between generated code. Use "Copy" for one-click copy or "Download File" to save as source code.
Use Cases
Case 1: Cross-language Regex Integration
Backend developers need the same regex validation in Python and Go. Input the regex once and get complete code for both languages, avoiding API-difference bugs.
Case 2: Full-stack Validation Consistency
Frontend JavaScript and backend Java/PHP need to share the same regex rules. The code generator ensures consistent regex logic and flags across all layers.
Case 3: Learning Regex Across Languages
Programming students compare regex API usage across languages to understand differences and commonalities, accelerating the learning curve.
Case 4: Interview Preparation
Regex questions are common in coding interviews. Use this tool to quickly verify regex correctness and understand multi-language implementations.
Technical Background
Regular expressions originated from Stephen Kleene's regular language theory in the 1950s. Language support varies: JavaScript uses built-in RegExp, Python has the re module, Go uses regexp (RE2 syntax, no backreferences), Java has java.util.regex, PHP uses PCRE functions, and Rust has the regex crate. Flag syntax also differs β JS uses /pattern/flags literals, Python uses re.IGNORECASE constants, Go uses (?i) inline flags. This tool handles these differences automatically, generating idiomatic code for each language.
β Which programming languages are supported?
JavaScript, Python, Go, Java, PHP, and Rust with match, replace, and extract operation modes.
β Can I use the generated code directly?
Yes, the code is complete and runnable with import statements and example usage included.
β Are regex flags supported?
Yes, g (global), i (case-insensitive), m (multiline), s (dotAll) flags are supported with auto-conversion to each language's native syntax.
β Is my data uploaded to a server?
No, all regex parsing and code generation happens locally in your browser.
β What if my regex has syntax errors?
The tool validates regex in real-time and shows specific error messages. Code updates automatically after fixing.
β Does Go support backreferences?
Go's regexp uses RE2 syntax which doesn't support backreferences or lookaround. The generated Go code will note this limitation.
β Can I batch generate all language codes?
Yes, click "Download All Languages" to get a file containing code for all six languages.