Online Tool Store
Regex Generator from Examples
Paste example strings and get a matching regex live as you type, then test new strings against it instantly. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown — replace it with your own example strings.
Generated pattern
How it works
- Paste a few example strings, one per line — the pattern updates live as you type.
- Common structure — digit runs, letter runs, fixed separators — is detected across all examples.
- A regular expression matching that structure is generated, with a "Copy" button.
- Paste any string into "Test a string against this pattern" to check whether it matches.
Generation compares character classes and positions across every example — digit runs, letter runs, fixed separators — and builds a pattern general enough to match the shared structure without requiring you to write regex syntax by hand. If the examples don't share the same structure, the tool says so rather than guessing at a pattern that would be wrong for some of them.
FAQ
Is my data uploaded anywhere?
No. Pattern generation happens entirely in your browser — your example strings are never sent to a server.
How many examples do I need?
Two or three consistent examples is usually enough to infer a reliable pattern; more examples produce a more accurate, generalized result.
What happens if my examples are inconsistent?
If they differ in length within the same structure (e.g. "A1" and "A12"), the pattern generalizes to match that range. If they have a genuinely different structure (different character types or segment counts), the tool tells you rather than generating a pattern that would silently be wrong for some of them — group similarly-shaped examples and generate separate patterns instead.
Can I test the generated pattern?
Yes — paste additional strings and the tool shows whether each one matches the generated pattern.
How we compare
| Feature | Online Tool Store | Writing regex by hand | AI assistants |
|---|---|---|---|
| No regex syntax knowledge needed | ✓ | Requires learning regex syntax | ✓ |
| Free, no sign-up | ✓ | ✓ | Often requires an account |
| Test new strings against the pattern instantly | ✓ | Needs a separate regex tester | Needs a follow-up prompt |