Regex Data Generator — Generate Sample Strings From a Pattern
Generate 1–100 strings that match any regex pattern. Great for test data, fixtures, and fuzzing.
samples
How to use
- 1 Type or paste a regex pattern. Don't wrap it in slashes — just the body.
- 2 Set the count slider (1–100).
- 3 Hit Sample for a phone-number example to see how the syntax works.
- 4 Copy the list or download as plain text.
Why use this tool
- Powered by <code class="font-mono text-xs">randexp</code> — generates strings that match a given regex.
- Library loaded lazily — page stays light.
- Great for seeding test data, fixtures, or fuzzing inputs.
- Pure client-side — your patterns and outputs stay local.
Frequently asked questions
Why are anchors stripped?
randexp builds strings from the pattern body — anchors (<code class="font-mono">^</code>, <code class="font-mono">$</code>) describe position rather than content, so they're removed automatically with a note above the output.
How is open-ended <code class="font-mono">.*</code> handled?
Quantifiers without a max bound are capped at 32 repetitions so output stays usable.
Can I use lookaheads or backreferences?
Lookarounds and backreferences are not supported by randexp's generation strategy. Most character classes, groups, alternation, and quantifiers do work.
What is Regex Data Generator?
A Regex Data Generator is a tool that produces strings matching a supplied regular expression pattern. It can generate from 1 to 100 results at a time, making it useful for creating test data, fixtures, and inputs for fuzzing. Running entirely in the browser, it lets developers build sample datasets from a regex without sending the pattern or output to a server.
Features
Pattern-driven
Generates strings that satisfy your regex, including character classes and quantifiers.
Batch 1–100
Produce up to 100 sample values at once for fixtures or datasets.
Honest limits
Anchors ^/$ are stripped and * / + are capped — a note explains any adjustment.
100% private
Runs client-side — the pattern and output never leave the browser.
Example
Input
\+1-[2-9]\d{2}-[2-9]\d{2}-\d{4}Output
+1-415-729-3084 (one representative match; each run is random)Common use cases
-
1
Generate test fixtures
Create realistic-looking phone numbers, SKUs, or IDs that match a required format.
-
2
Fuzz an input validator
Feed a validator many pattern-conforming strings to check edge cases.
-
3
Seed a database
Produce sample values matching a column's format constraint.
Zerethon's regex data generator produces random strings that match a regular expression, using the randexp library in your browser. Give it a pattern and a count (1–100) to build test fixtures, fuzzing inputs, or seed data. Because output is random, each run differs; anchors (^ and $) are stripped since randexp generates substrings, and unbounded quantifiers are capped for sane length.
- Category
- Developer
- Pricing
- Free
- Privacy
- Browser-based
- Signup
- Not required
References
Privacy
Your data never leaves your browser unless explicitly stated. Regex Data Generator runs entirely client-side — no server upload, no logging, no tracking of your input.
Learn the basics
Related tools
JSON Formatter
Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser.
Open toolSQL Formatter
Format SQL queries online — beautify MySQL, PostgreSQL, SQLite, SQL Server, Oracle, and BigQuery.
Open toolUUID Generator
Generate UUIDs online — v1, v4, v7, and Nil. Bulk generation up to 10,000. Free, no signup.
Open toolPassword Generator
Generate strong, cryptographically random passwords. Configurable length and character sets — runs in your browser.
Open toolBuild, share, and grow on Zerethon Social
Free signup. Earn points, collect achievements, and connect with creators worldwide.