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Regex Generator (simple)

Generate a simple regex pattern from a small text rule set like digits, words, prefix, or suffix.

Tool

Use this simple Regex Generator to create a basic regex pattern from straightforward text rules instead of writing the expression manually. It is useful for beginners, quick validation patterns, test input matching, forms, lightweight parsing tasks, and building common regex structures such as digits only, letters only, prefix match, suffix match, contains text, or exact match.

About this tool

Use this simple Regex Generator to create a basic regex pattern from straightforward text rules instead of writing the expression manually. It is useful for beginners, quick validation patterns, test input matching, forms, lightweight parsing tasks, and building common regex structures such as digits only, letters only, prefix match, suffix match, contains text, or exact match.

Use regex generator (simple) when you need a fast browser-based result without extra setup. It works well for quick checks, one-off tasks, and routine formatting or calculation work.

Learn more

Why use this tool

How to use

  1. Enter rules as JSON or key=value lines
  2. Use a mode such as exact, contains, startsWith, endsWith, digits, letters, alphanumeric, or customLengthDigits
  3. Click Run Tool to generate the regex
  4. Review the pattern and summary in the output
  5. Copy the regex into your app, form, or test case

Examples

Example

Input

mode=digits

Output

/^\d+$/

Useful for basic numeric field validation.

Example

Input

mode=startsWith
value=INV-

Output

/^INV\-/

Useful when values must begin with a fixed prefix.

Common errors

The mode is missing

Fix: Provide a supported mode such as exact, contains, startsWith, endsWith, digits, letters, alphanumeric, or customLengthDigits.

A required value field is missing

Fix: Modes like exact, contains, startsWith, and endsWith require a value.

The user expects a full AI regex engine

Fix: This page is for simple rule-based regex generation only.

The length value is invalid

Fix: Use a positive integer for rules like customLengthDigits.

Special characters break the intended literal match

Fix: The generator escapes regex-sensitive characters for literal-based modes.

FAQ

What does Regex Generator (simple) do?

It creates a basic regex pattern from simple rule-based input.

What modes does it support?

It supports simple modes like exact, contains, startsWith, endsWith, digits, letters, alphanumeric, and customLengthDigits.

Does it support advanced regex logic?

No. This page is focused on simple generation, not advanced regex authoring.

What input format can I use?

You can use JSON or key=value lines.

Why is this useful for beginners?

Because it turns small matching rules into ready-to-copy regex without requiring manual regex writing.

Use cases

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