Calculator
What the Regex Generator does
Regex Generator: generates Status, Regex pattern and JavaScript snippet from Pattern type, Flags and Custom: min length. Example: pattern type Email, flags gi and custom: min length 3 gives status Pattern ready.
This generator reads Pattern type, Flags, Custom: min length and Custom: require digits and produces Status, Regex pattern and JavaScript snippet. There is no submit step; the numbers move as you adjust them.
It is mostly used by anyone cleaning up machine output. Reading raw machine output is painful; a formatted view makes the structure obvious.
Nothing leaves the tab. You can watch your browser network panel while you use it and see for yourself.
Each field is explained further down, along with the method and a worked example that uses the default values.
What do the Regex Generator fields mean?
The Regex Generator uses 5 inputs. The starting figures are ordinary, not edge cases, so they make a sensible baseline.
| Field | What to enter | Default |
|---|---|---|
| Pattern type | choose from Email, URL (http/https), Phone (E.164-ish), IPv4, IPv6 (simple) or UUID | |
| Flags | optional | gi |
| Custom: min length | accepts 0 to 100 | 3 |
| Custom: require digits | choose from No or Yes | No |
| Test string (optional) | paste or type any amount of text | hello@yourstools.com https://yourstools.com 192.168.1.1 |
How does the Regex Generator work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same generated output.
Validation runs before the calculation, which is why a mistyped value shows an error rather than a plausible-looking result.
Worked example
These are the values the Regex Generator loads by default, and the result it produces from them. The defaults produce the result shown here; change any of them and the answer moves.
| Pattern type | |
|---|---|
| Flags | gi |
| Custom: min length | 3 |
| Custom: require digits | No |
| Test string (optional) | hello@yourstools.com https://yourstools.com 192.168.1.1 |
| Status | Pattern ready |
|---|---|
| Regex pattern | ^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}$ |
| JavaScript snippet | const re = /^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}$/gi; |
| Python snippet | import re pattern = r"""^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}$""" re.compile(pattern, re.I) |
| Test results | ✓ hello@yourstools.com ✗ https://yourstools.com ✗ 192.168.1.1 |
How to use it
- Pick a value for Pattern type: the options are Email, URL (http/https), Phone (E.164-ish), IPv4, IPv6 (simple) or UUID.
- Put Flags.
- Key in Custom: min length (0 to 100).
- Pick a value for Custom: require digits: the options are No or Yes.
- Paste your content into Test string (optional).
- Skip the submit button; there is not one. Editing is enough.
- Check Status, Regex pattern, JavaScript snippet, Python snippet and Test results on the right.
- If you need a record, Copy Link saves the inputs and Print produces a clean page.
What this tool does not do
- Processing happens in your browser, so very large inputs are bounded by available memory.
- Output follows the common convention for this format; a specific toolchain may have its own house style.
- Where a standard has revisions, the version used is the one named in the method section.
- The result inherits any error in the inputs without flagging it.
Frequently asked questions
Pattern type, Flags, Custom: min length, Custom: require digits and Test string (optional). That is the whole form. A starting value is in place for each, so you can change one value at a time and watch how the result responds.
Custom: min length accepts 0 to 100. Go outside it and you get an error against that specific field instead of a misleading number.
With the values loaded when the page opens, status comes out as Pattern ready. Edit any input and that figure moves with it.
No. Nothing is uploaded: useful when the text you are inspecting contains keys or customer records.
No cost and no account. Use it as often as you like.
It follows the standard definition for this operation, so the result matches what a reference implementation would give.