Example strings
Each line becomes a sample input for pattern generation.
Email pattern
High confidence/^[^\s@]+@[^\s@]+\.[^\s@]+$/iMatch standard email-style addresses.
Smart Regex Builder
Regex for IP Address Validation
Generate and test regex for IPv4 and IPv6 addresses in a browser-based regex builder that explains the pattern before you copy it.
- Generate from examples
- Test with live match highlights
- Copy for JS, TS, or Python
Quick modeAutosaves in this browser
Quick templates
Generated pattern
Use the generated regex as-is, or move it into test mode to tweak flags and cases.
/^[^\s@]+@[^\s@]+\.[^\s@]+$/igimsu
Live results
Generate, explain, and validate the pattern in one pass.
See the regex, what it means, and which test lines pass without digging through token noise.
Active regex
/^[^\s@]+@[^\s@]+\.[^\s@]+$/i3 lines • 3 matched • 0 unmatched
Pattern summary
Email pattern • High confidence
Match standard email-style addresses.
const regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/i;
Match results
One row per test string
Case 1
Matchedalex@example.com✔ Full line matched.
Case 2
Matchedmaya@company.io✔ Full line matched.
Case 3
Matchedtest.user@site.dev✔ Full line matched.
What this regex matches
- Matches the full line from start to end.
- Requires text before and after @.
- Ignores letter case.
- Matches all 3 current test lines.
Show detailed breakdown
^Start of string
Match from the start of the string.
[^\s@]+One or more character outside sets
Match one or more character outside sets.
@@ symbol
Match the @ character.
[^\s@]+One or more character outside sets
Match one or more character outside sets.
\.Literal .
Match the literal character ..
[^\s@]+One or more character outside sets
Match one or more character outside sets.
$End of string
Match up to the end of the string.
Why it helps
Why generate IP address regex with a builder
Validate IPv4 octet ranges correctly instead of accepting anything shaped like four numbers.
Test valid addresses and invalid near-misses like 256.1.1.1 side by side.
Read a plain-English explanation of the octet groups so the rule stays maintainable.
How to use it
How to build an IP address regex
1 Paste addresses that should match, like 192.168.1.1 or 10.0.0.255.
2 Add out-of-range and malformed samples that should fail.
3 Review the generated pattern and explanation, then copy it into log filters or validation code.
Quick tips
IP address regex tips
A correct IPv4 octet is (25[0-5]|2[0-4]\d|1\d{2}|[1-9]?\d) — repeat it four times with dots; \d{1,3} alone accepts 999.
Full IPv6 regex is long due to :: compression — for validation, a parser or library is usually safer than a hand-rolled pattern.
For grep and log filtering, escape the dots: 192\.168\. — an unescaped dot matches any character.
FAQ
IP address regex questions
Can this generate regex for IPv4 addresses?
Yes. Add sample addresses and the builder generates a pattern you can test against valid addresses and out-of-range failures.
Why does \d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3} accept invalid IPs?
Because it allows any 1–3 digit number, including 999. Each octet needs an explicit 0–255 range group to reject out-of-range values.
Can regex validate IPv6 addresses?
Yes, but the pattern is long because of zero compression and mixed notation. For strict IPv6 validation, a parser is often the better tool.
Can I use the IP regex in grep or log searches?
Yes. Test the pattern against sample log lines first, and remember to escape dots so they match literally.
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