Generate Regular Expressions Free — Describe Your Pattern
No more deciphering cryptic syntax. Tell the AI what pattern you need and get a working regex in seconds — free, unlimited, no signup required.
Free forever · no signup · no credit card · unlimited
import os
# Folder to clean up — change this to your path
FOLDER = "./photos"
for i, name in enumerate(sorted(os.listdir(FOLDER)), start=1):
src = os.path.join(FOLDER, name)
if not os.path.isfile(src):
continue
ext = os.path.splitext(name)[1].lower()
dst = os.path.join(FOLDER, f"photo_{i:03d}{ext}")
os.rename(src, dst)
print(f"{name} -> {os.path.basename(dst)}")This script renames every file in a folder to photo_001, photo_002, and so on, keeping each file’s extension. Set FOLDER to your folder, then run python rename.py from a terminal.
This free regex generator creates regular expressions from plain-English descriptions. Regular expressions are powerful tools for matching, validating, and extracting text patterns — but writing them by hand is notoriously difficult. Describe what you need to match and get a working regex instantly, no prior knowledge required.
How to Generate a Regular Expression
Describe your pattern
Explain in plain English what text you need to match, validate, or extract. Be specific: mention examples of valid and invalid inputs if you can.
Click Generate
The AI writes a regular expression that matches your description and provides a brief explanation of how it works.
Test the regex
Copy the regex and test it at regex101.com or regexr.com — paste your regex and some sample text to verify it matches correctly.
Use it in your code
Paste the regex into your Python, JavaScript, SQL, or other language code. The generator shows the correct syntax for the language you specify.
About This Regex Generator
Regular expressions (regex or regexp) are sequences of characters that define a search pattern. They are built into almost every programming language and are used for tasks like validating form inputs, parsing log files, extracting data from text, find-and-replace in editors, and filtering database records. Learning regex from scratch takes time because the syntax is dense and easy to get wrong — this generator lets you get results immediately while you learn.
Some of the most common regex use cases include email validation (checking that an input looks like a valid email address), phone number matching (handling multiple formats like US, international, or formatted with dashes and parentheses), date validation (ensuring dates follow a specific format like YYYY-MM-DD or MM/DD/YYYY), URL matching (checking for valid http or https URLs), and extracting substrings (pulling numbers, hashtags, or codes from a larger body of text).
Key metacharacters you will encounter in generated regexes: . matches any character. * means zero or more of the previous item. + means one or more. ? means zero or one (optional). ^ anchors to the start of the string. $ anchors to the end. \d matches any digit. \w matches word characters (letters, digits, underscore). \s matches whitespace. Square brackets [abc] match any character inside them. Parentheses () create capture groups.
Using regex in Python is done via the built-in re module. Common patterns: re.match() checks for a match at the start of a string. re.search() finds a match anywhere in the string. re.findall() returns all matches as a list. re.sub() replaces matches with a new string. Example: import re; result = re.match(r'^[\w.-]+@[\w.-]+\.\w{2,}$', email).
In JavaScript, regex literals are written between forward slashes: /pattern/flags. Use string.match(), string.replace(), string.test(), or the RegExp object. Example: /^[\w.-]+@[\w.-]+\.\w{2,}$/.test(email).
In SQL, most databases support a REGEXP or SIMILAR TO operator. PostgreSQL uses ~ for case-sensitive and ~* for case-insensitive matching. MySQL uses REGEXP. Example: SELECT * FROM users WHERE email ~ '^[\w.-]+@'.
For testing and debugging your regex before putting it in code, use free online tools: regex101.com shows matches highlighted in real time with a full explanation of each part of the pattern. regexr.com is another popular option with community-shared patterns. Always test your regex against both valid and invalid examples before deploying it.
Frequently asked questions
Is this regex generator really free?
Yes, completely free. No account or signup needed. Generate as many regular expressions as you like.
Which programming languages does it support?
The generator produces regex that works in Python, JavaScript, Java, PHP, Ruby, SQL, and most other languages. Specify your language in the description for language-specific syntax.
How do I test the generated regex?
Copy it and paste it into regex101.com or regexr.com. Paste your sample text and you will see which parts match, highlighted in real time.
Can regex match any text pattern?
Regex is very powerful but has limits. Nested structures like HTML or JSON are better handled by dedicated parsers. For most flat text patterns — emails, phones, dates, codes — regex works very well.
Do I need to know regex to use this?
Not at all. Describe what you need in plain English and the AI writes the regex. The explanation provided helps you understand what was generated.
Will the generated regex always be correct?
The AI generates accurate patterns for well-described use cases, but always test with your actual data before using in production. Edge cases may require tweaks.