What is Regex and Why You Need a Regex Builder

Regular expressions (regex) are powerful patterns used to match, search, and manipulate text. This free regex builder helps you create and test regex patterns specifically optimized for n8n workflow automation.

The Problem: Complex Pattern Matching

When building n8n automations, you often need to extract specific data from text, validate formats, or filter content based on patterns. Writing regex from scratch is error-prone and testing patterns manually is time-consuming.

• Extracting emails, phone numbers, or URLs from unstructured text
• Validating input formats before processing in workflows
• Parsing API responses to extract specific data
• Filtering webhook payloads based on content patterns

The Solution: Visual Regex Builder with Live Testing

This free regex tester provides instant visual feedback as you build patterns. See matches highlighted in real-time, test against sample data, and use pre-built patterns for common n8n use cases.

Common Regex Use Cases in n8n

• Email Validation - Verify email addresses before sending notifications
• Data Extraction - Pull specific values from API responses
• URL Parsing - Extract domains, paths, or query parameters
• Log Analysis - Parse error messages and extract error codes
• Content Filtering - Route data based on text patterns

Why Choose This Regex Builder?

• Free Forever - No sign-up or usage limits
• n8n-Focused - Pre-built patterns for common automation tasks
• Live Testing - See matches highlighted instantly
• Capture Groups - Extract specific parts of matches
• Quick Reference - Built-in cheat sheet for regex syntax

Pre-Built Regex Patterns

• Email Address Pattern: ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$
• Phone Number Pattern: ^\+?[1-9]\d{1,14}$
• URL Pattern: ^https?:\/\/[\w\-]+(\.[\w\-]+)+[\/#?]?.*$
• IPv4 Address Pattern
• UUID Pattern
• Date Pattern (YYYY-MM-DD)
• Credit Card Pattern
• JSON Key Extraction Pattern

Regex Syntax Cheat Sheet

. (dot)

Any character except newline

\d

Digit (0-9)

\w

Word character (a-z, A-Z, 0-9, _)

\s

Whitespace

^

Start of string

$

End of string

*

Zero or more occurrences

+

One or more occurrences

?

Zero or one occurrence

{n}

Exactly n times

{n,m}

Between n and m times

[abc]

Character class - matches a, b, or c

[^abc]

Negated character class - matches anything except a, b, or c

(abc)

Capture group - captures and groups abc

a|b

Alternation - matches a or b

How to Use Regex in n8n Workflows

In Function Nodes

You can use JavaScript regular expressions in Function nodes to match and extract data

In IF Nodes (Regex Match)

Use the "Regex" operation in IF nodes to filter data based on pattern matches. Enable case-insensitive matching with the "i" flag.

For Data Extraction

Use capture groups () to extract specific parts of matched text. Access groups with match[1], match[2], etc.

Related Tools

• Expression Playground - Test n8n expressions
• JSON Path Tester - Extract data from JSON
• Error Decoder - Decode n8n errors
• JSON Formatter - Format and validate JSON