Regex generator

Run on September 28, 2026: 5 inputs on 16 models, each with this tool's own instructions.

Write one regular expression for this. Put the pattern alone in a code block first, then explain each part and give strings it matches and doesn't.

---
A password with at least 10 characters, at least one uppercase letter, one lowercase letter, one digit and one symbol from !@#$%^&*, and no spaces.

```regex
/^(?=.*[A-Z])(?=.*[a-z])(?=.*\d)(?=.*[!@#$%^&*])\S{10,}$/
```

Assumption: “no spaces” means no whitespace characters, including tabs and line breaks.

- `^` and `$` require the entire password to match.
- Each `(?=...)` lookahead requires at least one uppercase letter, lowercase letter, digit, and permitted symbol.
- `\S{10,}` requires at least 10 non-whitespace characters.

Matches: `Abcdefg1!x`, `PassWord9#z`, `A1!bcdefghij`

Doesn’t match: `abcdefghi1!` (no uppercase), `ABCDEFGHI1!` (no lowercase), `Abcdefghi1` (no permitted symbol)

Assumption: the whole string must be exactly the password — no leading/trailing spaces either, since no spaces are allowed anywhere.

```javascript
/^(?=.*[A-Z])(?=.*[a-z])(?=.*\d)(?=.*[!@#$%^&*])\S{10,}$/
```

- `^` and `$` — match the whole string, not just part of it.
- `(?=.*[A-Z])` — lookahead requiring at least one uppercase letter.
- `(?=.*[a-z])` — lookahead requiring at least one lowercase letter.
- `(?=.*\d)` — lookahead requiring at least one digit.
- `(?=.*[!@#$%^&*])` — lookahead requiring at least one of the allowed symbols.
- `\S{10,}` — 10 or more non-whitespace characters, which also enforces the "no spaces" rule.

Matches:
- `Abcdef1!xyz`
- `Passw0rd!Long`
- `Xy9#aaabbbccc`

Doesn't match:
- `abcdef1!xyz` (no uppercase)
- `Abcdef1xyzAB` (no symbol)
- `Abc de1!xyz` (contains a space)

1. Describe what to match, with an example or two of what should and shouldn't. Up to 1,000 characters.

2. Pick your language's regex flavour.

3. Press “Write the regex”. Without an account you see the start (1 free run a day, no account needed).

4. Paste the pattern into the tester below and try it on your own strings, including ones it should reject.

• Give a yes and a no

  “Matches ORD-2026-00417 but not ORD-26-417” tells the generator more than a paragraph. Give one string that should match and one that shouldn't.

• Whole value or search?

  Validating a whole field and finding matches inside a longer text need different patterns. Say which one you want.

• Try the edges

  Test the edge cases: an empty string, extra spaces, lower case, the longest value you expect. That's where patterns break.

• Save your test strings

  Keep the tester's strings as a comment next to the regex in your code. Next time someone changes it, they can run them again.

• It rejects what it should

  Try it on strings it should reject, not only ones it should match. Most wrong regexes match too much: an email pattern that accepts “a@b”, a date that accepts month 13.

• Anchored when it validates

  A pattern that checks a whole value (a postcode, an ID) needs ^ at the start and $ at the end. Without them, “abc12345xyz” passes a five-digit check.

• No runaway backtracking

  Nested repeats like (a+)+ can take seconds, or forever, on a long string. A good pattern is plain enough that you can read it.

• Your language's flavour

  JavaScript, Python and PCRE differ in small ways (lookbehind, named groups, flags). The pattern should be in the flavour your code uses.

• Without an account: 1 free run a day, on GPT-6 Luna, shared with the free message on our home page. It takes up to 1,000 characters, writes up to about 600 tokens (roughly 450 words), and shows you the start of the regex.

• Signing up is free, with an email link and no card. llmwise accounts are for people 18 and older. The regex you ran comes with you as your first chat, and you get 5 free messages on almost every model (all but Claude Fable 5.1, Claude Opus 5.5, and GPT-6 Astra).

• Signed in, the tool runs on the model you pick, on your plan, shows the whole answer, and you can carry on in the chat with any model, or ask another model the same thing.

More free tools are on the tools page, and what each plan gives is on pricing.