Base64 Encoder / Decoder

URL Encoder / Decoder converts text to and from percent-encoding with the browser's encodeURIComponent and decodeURIComponent. It escapes one URL component — a single query-string value or path segment — not a whole address: a full URL run through Encode comes back with :// turned into %3A%2F%2F. The characters A-Z, a-z, 0-9 and - _ . ! ~ * ' ( ) are left untouched; spaces, &, =, /, ?, # and the rest are escaped. Decode reverses it and reports a clear error on a malformed % sequence; a + is left as a literal plus, not turned into a space. Unlike the Base64 Encoder it keeps text readable and only escapes unsafe characters, and unlike URL Parser & Analyzer it transforms a fragment rather than splitting a full URL into parts. Input is limited to 2 MB and stays in the browser.

Generate a random UUID (version 4) in your browser — click Generate to get a fresh, RFC 4122-compliant identifier, then copy it with one click or generate another. Every UUID is produced using your browser's cryptographically secure random number generator (the Web Crypto API), the same source used for encryption keys, never a weak pseudo-random fallback — if that secure API isn't available, a clear error is shown instead of silently generating a lower-quality identifier. It is handy when you need a unique identifier for a database record, a test fixture, or a temporary key while prototyping. Everything runs locally in your browser, so no identifier you generate is ever sent to a server or stored anywhere.

Generate a SHA-256, SHA-384, or SHA-512 hash from text in your browser — type or paste your text, choose an algorithm, and get the hexadecimal digest immediately, using your browser's native Web Crypto API rather than a custom implementation. A SHA hash is one-way: it produces a fixed-length fingerprint of the input that cannot be reversed back into the original text, which is exactly what's useful for verifying that a piece of text or a downloaded value matches an expected digest, or generating a deterministic identifier from text content. SHA hashing is not encryption, and hashing a password directly with SHA is not a secure way to store passwords — dedicated password-hashing algorithms with salting exist for that purpose and are outside the scope of this tool. Everything runs locally in your browser, so no text you enter is ever sent to a server or stored anywhere.

Regex Tester runs your pattern with the browser's own JavaScript regular expression engine — the same RegExp behaviour you get in Node or a browser console, not PCRE, Python, Java, or .NET. Enter a pattern, pick the flags you need (g, i, m, s, u, y, and d for match indices), and paste the text to test against. It reports how many matches were found and how many capture groups the pattern declares, then lists every match with its start and end position, its numbered groups, and any named groups such as (?<year>\d{4}); a group that did not participate is shown as undefined rather than an empty string. The test text is redrawn with each match highlighted and numbered, so overlaps and zero-length matches stay visible. A replacement field applies JavaScript's native syntax — $&, $1, $<name>, $$ — and without the g flag only the first match is replaced. Each run executes in a dedicated Web Worker: long-running expressions are stopped after one second and the worker is discarded, which limits page freezes without being a guarantee against every pathological pattern. Beyond a yes/no match check it surfaces every group, previews replacements, and highlights results inline; a compact cheatsheet covers the common tokens. Everything runs in your browser and nothing you paste is uploaded.