Regex Builder & Tester

Build, test, and understand regular expressions

Create regex patterns with visual tools, test against multiple strings, and get plain English explanations. Perfect for developers, AI builders, and anyone working with text validation and pattern matching.

🎯

Visual Pattern Builder

Choose from 100+ pre-built patterns across 15 categories or build your own with visual guidance

⚡

Real-time Testing

Test patterns against multiple strings simultaneously with instant match highlighting

📚

Plain English Explanations

Understand what your regex patterns do with automatic explanations and examples

🤖

AI Pattern Validation

Perfect for testing and validating regex patterns generated by ChatGPT, Claude, and other AI models

Flags:

Common Use Cases

Email Validation

Validate email addresses in forms and user input

Phone Number Extraction

Extract phone numbers from text in various formats

URL Matching

Find and validate URLs in text content

Data Extraction

Extract structured data like dates, IDs, or codes

Perfect for Modern Builders

Professional Developers

Build complex regex patterns for validation, parsing, and text processing in applications

💡 Create patterns for API validation, log parsing, and data extraction workflows

AI Builders

Test and validate regex patterns generated by ChatGPT, Claude, and other AI models

💡 Verify AI-generated regex patterns work correctly before implementing in your projects

No-Code Creators

Build validation rules for forms and data processing without complex regex knowledge

💡 Create email, phone, and custom validation patterns for Bubble, Webflow, and Zapier

How It Works

Step-by-Step Process

1Type your regex pattern or select from our library of common patterns
2Enter multiple test strings to validate your pattern against different inputs
3See matches highlighted, get explanations, and copy in multiple formats

Regex Fundamentals & Common Patterns

  • Basic Patterns: Use . for any character, * for zero or more, + for one or more, and ? for optional. Combine with character classes like [a-z] or [0-9].
  • Anchors & Boundaries: Use ^ for start of line, $ for end of line, and \b for word boundaries. These ensure your pattern matches exactly where you expect.
  • Capture Groups: Use parentheses () to capture parts of your match. Access captured groups in replacements or use (?:...) for non-capturing groups to group without capturing.
  • Common Gotchas: Escape special characters with backslash \. Remember that .* is greedy (matches as much as possible) - use .*? for non-greedy matching.
  • Testing Strategy: Always test with edge cases: empty strings, very long strings, and strings that almost match. Use multiple test cases to ensure your pattern works reliably.

Frequently Asked Questions

What types of tools does BuilderTools.dev offer?

We provide specialized micro-tools for data conversion, AI development, CSS calculations, API cost estimation, and project planning. All tools are designed to work seamlessly with modern development workflows including AI-assisted building and no-code platforms.

Are BuilderTools.dev tools free to use?

Yes! All our basic tools are completely free with no registration required. We're building premium features for power users, but our core mission is providing essential utilities that every builder can access instantly.

How do these tools help with AI-assisted development?

Our tools are optimized for AI workflows. Convert data to AI-friendly formats, estimate API costs before building, validate AI outputs, and handle technical calculations while you focus on prompting and creating.

Can I integrate BuilderTools with my existing workflow?

Absolutely! Our tools work great with ChatGPT, Claude, Zapier, Make, Bubble, Webflow, and traditional development environments. Copy-paste results anywhere or use our upcoming API for programmatic access.