Rahul Smoothy: Circuit Cove

Regex Tester — Test Regular Expressions Live

← Circuit CoveThe Creative Island · Island 08

Paste a pattern, paste your text — every match lights up. Case-sensitivity and global flags included.

Pattern (without slashes)

Flags

Test text

How to use this tool

Type your pattern without the surrounding slashes.
Choose flags: g finds all matches, i ignores case, m makes ^ and $ match line ends.
Watch matches highlight live as you type; errors explain themselves.

Example

Pattern \b\w+@\w+\.\w+\b on the sample text highlights both email addresses. Try \d+ to catch numbers, or ^(.{0,20}) with the m flag to grab line starts.

The formula

matches = String.prototype.matchAll semantics, with zero-length-match protection

What the result means

Every highlighted span is one match, in order, exactly where the engine found it. The match list shows what the regex actually captured — often revealing that a pattern is greedier or looser than intended. If the badge says INVALID, the message is the engine's own diagnosis.

Frequently asked questions

Why doesn't my pattern with slashes work?

Enter only the pattern itself — /pattern/flags is JavaScript syntax; this tool takes the pattern in the box and flags from the dropdown.

What is a zero-length match and why guard it?

Patterns like \b or (?=x) can match empty strings; without protection the engine loops forever at the same spot. The tool steps past such matches safely.

Can I use capture groups?

Yes — JavaScript syntax ($1, named groups) all work; the highlight shows full matches, and groups are visible when you use them in your own replacement code.

Is my text or pattern uploaded?

No — the engine runs in your browser; logs, keys and secrets stay on your device (though as a habit, avoid pasting real secrets into any web page).

More tools from Circuit Cove

JSON FormatterPretty print JSON Base64 Encoder/DecoderEncode or decode text HTML Entity EncoderEscape HTML safely Timestamp ConverterUnix time to date

Explore the island world

Circuit Cove — the island where this tool lives.
The Main Island — drive the boat, explore the whole world.
The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: all processing happens locally in your browser — never paste production secrets or private data into any online tool, including this one. · Privacy Policy · Disclaimer

Timestamp Converter — Unix Time to Date (Both Ways)

← Circuit CoveThe Creative Island · Island 08

Epoch ↔ human date, in both directions — seconds, milliseconds, your local timezone.

Unix timestamp (seconds or milliseconds)

Or pick a date & time → timestamp

How to use this tool

Paste a Unix timestamp (seconds or milliseconds — the tool detects which) to see the human date in your timezone.
Or pick a date & time to get its timestamp, in seconds, milliseconds and ISO format.
Use current time fills both sides with now.

Example

1783639200 (seconds) = a moment in July 2026 — paste it and the tool shows the exact date and time in your timezone, plus the milliseconds form 1783639200000.

The formula

timestamp = milliseconds since 1 January 1970 00:00 UTC (Unix epoch)

What the result means

Unix time counts every second since 1970-01-01 UTC — the shared calendar of servers and databases. The tool auto-detects seconds vs milliseconds by magnitude (13-digit values are ms). The date shown is in your local timezone, which is why the same timestamp can 'mean' different hours to different people.

Frequently asked questions

Why does the same timestamp show different times for different people?

Timestamps are absolute (UTC-based); the clock you read is local. That's correct behavior — the moment is identical, only the timezone label differs.

Seconds or milliseconds — how do I know which I have?

10-digit numbers are seconds (until year 2286); 13-digit are milliseconds. The tool detects this automatically and labels the result.

What about dates before 1970?

They exist as negative timestamps — the tool handles them; seconds and ms both work backwards from the epoch.

Is my data private?

Yes — conversions happen entirely in your browser.

More tools from Circuit Cove

UUID GeneratorRandom UUIDs Base64 Encoder/DecoderEncode or decode text JSON FormatterPretty print JSON Date Difference CalculatorOn Clocktower Town

Explore the island world

Circuit Cove — the island where this tool lives.
The Main Island — drive the boat, explore the whole world.
The 90s Kids Island — where most of us started.

HTML Entity Encoder & Decoder — Escape HTML Safely

← Circuit CoveThe Creative Island · Island 08

Make HTML safe to display — turn <script> into harmless text, or decode entities back to characters.

Input

Output

How to use this tool

Choose Encode (escape for safe display) or Decode (entities → characters).
Paste your HTML or text.
Press Convert.

Example

Encode <b>bold</b> for display → <b>bold</b> — the browser then shows the tags as text instead of rendering them. Decode reverses it, including named entities like © → ©.

The formula

escape: & < > " ' → & < > " ' | unescape: entities rendered via a detached DOM element

What the result means

Encoding is the first line of defense against XSS: angle brackets become harmless text, so user input can never become executable markup. The five characters escaped here are the exact set recommended by OWASP for HTML context — more is unnecessary, less is unsafe.

Frequently asked questions

Is this the same as URL encoding?

No — URL encoding (%20) is for links; HTML entities (<) are for page content. Different worlds, different escapes. The URL tool handles the other one.

Why only five characters when encoding?

Because those five are the ones that change HTML structure (& starts entities, < > make tags, quotes break attributes). Escaping more just bloats the text.

Does decoding execute any code?

Never. The decoder renders entities into a detached textarea and reads back plain text — no script runs at any point.

Is my text uploaded?

No — everything happens locally in your browser.

More tools from Circuit Cove

Base64 Encoder/DecoderEncode or decode text URL Encoder/DecoderEncode URLs safely JSON FormatterPretty print JSON Markdown PreviewerOn Paper Port

Explore the island world

Circuit Cove — the island where this tool lives.
The Main Island — drive the boat, explore the whole world.
The 90s Kids Island — where most of us started.

UUID Generator — Free UUID v4 Online

← Circuit CoveThe Creative Island · Island 08

Cryptographically random UUIDs (v4) — generate one or a hundred, copy in one click.

How many? (1–100)

Uppercase?

How to use this tool

Set how many UUIDs you want (1–100).
Press Generate — each is a fresh version-4 UUID from your device's cryptographic random source.
Toggle uppercase for Microsoft-style GUIDs; Copy all grabs the list.

Example

3f8a2c91-7b4d-4e1a-9c5f-2d6e8a01b3c7 — the 4 in the third group marks version 4; the 8/9/a/b first digit of the fourth group marks the variant.

The formula

UUID v4 = 122 random bits + 6 fixed version/variant bits, formatted as 8-4-4-4-12 hex

What the result means

A v4 UUID has about 5.3 × 10³⁶ possible values — generating billions per second for a lifetime still makes collisions practically impossible. That's why databases, distributed systems and session tokens use them instead of incrementing IDs.

Frequently asked questions

Are these UUIDs safe to use in production?

Yes — they come from your browser's cryptographic RNG (crypto.randomUUID with a getRandomValues fallback). For cryptographic keys, use a purpose-built key generator instead.

Can a UUID repeat itself?

Practically no. You would need to generate ~2.7 quintillion IDs for a 50% collision chance — the 'birthday bound' of 122 random bits.

What's the difference between UUID and GUID?

Same idea, one byte longer vs shorter spelling: GUID is Microsoft's name for the RFC 4122 UUID. The uppercase toggle gives you the classic GUID look.

Could two visitors get the same UUID?

Each browser generates independently, but the keyspace is so large that it doesn't matter — this is exactly the property UUIDs were designed for.

More tools from Circuit Cove

Random Token GeneratorOn Safe Harbor Base64 Encoder/DecoderEncode or decode text Hash GeneratorOn Safe Harbor JSON FormatterPretty print JSON

Explore the island world

Circuit Cove — the island where this tool lives.
The Main Island — drive the boat, explore the whole world.
The 90s Kids Island — where most of us started.

URL Encoder & Decoder — Percent-Encoding Tool

← Circuit CoveThe Creative Island · Island 08

Turn spaces and symbols into %20-safe URL text — or decode a messy link back to human.

Input

Output

How to use this tool

Choose Encode or Decode.
Paste your URL or text.
Press Convert — swap direction with one click.

Example

Encode ?q=creative island & tools → ?q=creative%20island%20%26%20tools. The space becomes %20 and the & becomes %26 so it can not be mistaken for a parameter separator.

The formula

encode: encodeURIComponent(text) | decode: decodeURIComponent(text)

What the result means

URLs may only contain a limited set of characters, so everything else travels percent-encoded: % = the escape, two hex digits = the byte. Encoding a whole URL vs just a value differs (encodeURI keeps ://?& intact) — this tool encodes values, which is what you want for query strings and slugs.

Frequently asked questions

Should I encode the whole URL or just the parameter?

Just the value. Encoding the full URL turns :// into %3A%2F%2F and breaks it. Type the value you want to pass (a search phrase, a slug) and encode that.

Why do some sites show + instead of %20?

That's the older form-urlencoded style, where + means space in form data. The decoder here accepts both.

My decoded text shows weird characters — why?

The original was encoded in a different charset (often Latin-1). Percent-decoding is exact; interpreting the bytes requires knowing their encoding.

Is my URL data uploaded?

No — the conversion happens locally in your browser.

More tools from Circuit Cove

Base64 Encoder/DecoderEncode or decode text HTML Entity EncoderEscape HTML safely JSON FormatterPretty print JSON Slug GeneratorOn Paper Port

Explore the island world

Circuit Cove — the island where this tool lives.
The Main Island — drive the boat, explore the whole world.
The 90s Kids Island — where most of us started.

Base64 Encoder & Decoder — UTF-8 Safe

← Circuit CoveThe Creative Island · Island 08

Encode text to Base64 or decode it back — Unicode-safe, so Bangla and emoji survive the round trip.

Input

Output

How to use this tool

Choose Encode (text → Base64) or Decode (Base64 → text).
Type or paste your input.
Press Convert — use Use output as input to reverse the operation in one click.

Example

Encode: Hello, Island! → SGVsbG8sIElzbGFuZCE=. Decode it back and you get the original — even with Bangla text or emoji, because the tool is UTF-8 safe.

The formula

Base64 = btoa(utf-8 bytes of text); text = utf-8 decode of atob(Base64)

What the result means

Base64 represents any byte sequence using 64 safe characters (A–Z, a–z, 0–9, +, /) — built for systems that only handle plain text, like data-URI images, email attachments and JSON web tokens. Output grows ~33% larger than the input: 3 bytes become 4 characters.

Frequently asked questions

Why is Base64 not encryption?

Because anyone can decode it instantly — it's an encoding, not a secret. 'Base64 hiding' is security by obscurity and protects nothing.

Why did my decode fail?

Base64 must contain only its alphabet and optional = padding, and (usually) a length divisible by 4. Line breaks are tolerated; stray characters are not.

Does it handle Bangla and emoji?

Yes — the tool encodes through UTF-8 bytes first, which is the correct method. Naive btoa() on non-ASCII text is exactly the bug this avoids.

Is my text uploaded?

No — encoding happens entirely in your browser.

More tools from Circuit Cove

URL Encoder/DecoderEncode URLs safely HTML Entity EncoderEscape HTML safely JSON FormatterPretty print JSON Hash GeneratorOn Safe Harbor

Explore the island world

Circuit Cove — the island where this tool lives.
The Main Island — drive the boat, explore the whole world.
The 90s Kids Island — where most of us started.

JSON Formatter & Validator — Pretty Print or Minify

← Circuit CoveThe Creative Island · Island 08

Paste messy JSON — get it pretty-printed, validated, or minified. Errors point to where the string broke.

Your JSON

How to use this tool

Paste your JSON into the box.
Press Format (pretty) for readable indented JSON, or Minify for the smallest production string.
Invalid JSON shows the error and its position; valid JSON shows size stats and a preview.
Copy result puts the output on your clipboard.

Example

Input: {"b":2,"a":[1,2,3]} → formatted:

{"b": 2,
 "a": [
  1,
  2,
  3
 ]
}

Minified: {"b":2,"a":[1,2,3]}

The formula

validation = JSON.parse(); pretty = JSON.stringify(obj, null, 2); minify = JSON.stringify(obj)

What the result means

A valid badge means the parser could build a complete object from your text — the same engine every browser uses. The char-saved figure tells you how much the minified version will shrink your payload. Errors include the position, so a missing comma is a 10-second fix instead of a 10-minute hunt.

Frequently asked questions

Is my JSON sent anywhere?

No. Parsing, formatting and minifying all happen in your browser — API responses and config files never leave your device. Never paste credentials into any online tool anyway, even this one.

Why does my JSON fail with 'Unexpected token'?

The three classics: trailing commas, single quotes instead of double quotes, and comments — JSON allows none of them. The error position points to the first offender.

Does it preserve key order?

Yes — modern JavaScript objects preserve insertion order for string keys, so your keys stay in the order they appear.

Can it handle big files?

Comfortably into the hundreds of KB. Multi-megabyte JSON may slow the page — the browser's parser is the limit, not this tool.

More tools from Circuit Cove

Base64 Encoder/DecoderEncode or decode text URL Encoder/DecoderEncode URLs safely HTML Entity EncoderEscape HTML safely Timestamp ConverterUnix time to date

Explore the island world

Circuit Cove — the island where this tool lives.
The Main Island — drive the boat, explore the whole world.
The 90s Kids Island — where most of us started.