tulzy — Free Online Developer Tools: JSON, Base64, UUID

Encoding

Base64

Base64 encode and decode — text and files, right in your browser.

Base32

Base32 (RFC 4648) encode and decode — text and files, right in your browser.

URL Encode/Decode

Encode and decode URLs — characters that need escaping in links and query parameters.

HTML Entities Encode/Decode

Encode and decode HTML entities — safely display special characters on a page.

JWT Encoder/Decoder

Encode and decode JWT tokens — header, payload, HMAC signing, and standard claims.

Unicode Escape

Encode and decode Unicode escape sequences — characters as \uXXXX and back.

Caesar cipher — a cyclic shift of Latin alphabet letters. ROT13 is the special case with shift 13 (button below), symmetric: encode and decode give the same result. Other characters (digits, punctuation, non-Latin letters) are left unchanged.

Punycode encode/decode

Encode internationalized domain names (IDN) with unicode characters into ASCII-compatible Punycode (xn--) and back.

Morse code encode/decode

Encode text (Latin and Cyrillic) into Morse code (dots and dashes) and back. Characters without a table entry are skipped.

Data URI / Base64 image

Encode an image into a Data URI (data:image/…;base64,…) for embedding in CSS/HTML, and decode a Data URI or raw Base64 back into a file — all in your browser.

Gzip/Deflate ↔ Base64

Compress text with Gzip or Deflate, then Base64-encode the result — and back. Powered by the Compression Streams API, right in your browser.

XML Entities Encode/Decode

Encode and decode XML entities — the 5 predefined ones (ampersand, angle brackets, apostrophe, quote) and numeric character references.

JSON

JSON Formatter / Minify / Validator

Format (2-space indent), minify, and validate JSON right in your browser.

JSONPath Tester

Test JSONPath expressions against real JSON data — instantly see the matched values and their paths.

JSON Diff / Compare

Compare two JSON documents — what was added, removed, or changed, with an exact path to each difference.

JSON Schema Validator

Validate JSON data against a JSON Schema (draft-07 style) — with an exact path and explanation for every violation.

JSON Path Extractor / Flatten

Flatten nested JSON into a flat "path: value" list, and rebuild it back into a nested structure (Unflatten). Path notation matches JSONPath/JSON Diff: store.book[0].price.

JSON Sort Keys

Recursively sort JSON object keys alphabetically — array element order is left untouched, only object keys at every nesting level.

JSON Repair

Fix broken JSON — trailing commas, single quotes, unquoted keys, comments, Python literals (True/False/None), and more — with a full list of every fix applied.

Mock JSON Generator

Generate fake JSON data from a template: placeholder values like {{name}} or {{email}}, and arrays repeated via "key|N".

JSON ↔ YAML / CSV / XML / TOML

Convert JSON to YAML, CSV, XML, or TOML and back — entirely in the browser, no libraries.

Text

Case Converter

Convert text or an identifier into every common naming style at once — camelCase, snake_case, kebab-case, and more. Recognizes word boundaries in camelCase/PascalCase, acronyms (XMLParser → XML + Parser), and around digits.

Text Diff

Compare two texts line by line — what was added, removed, or changed, with word-level highlighting inside changed lines.

Regex Tester / Find & Replace

Test regular expressions against real text: highlighted matches with parsed capture groups, or replace matches with new text.

Sort & Dedupe Lines

Sort lines of text alphabetically, remove duplicates, empty lines, and extra whitespace.

String Escape

Escape text into a string literal (quotes, backslash, control characters) for pasting into code, or unescape it back.

CRLF ↔ LF Converter

Convert line endings between Windows (CRLF), Unix/macOS (LF), and classic Mac (CR), with mixed-ending detection.

Character & Word Counter

Real-time text statistics: characters (with and without spaces), words, lines, sentences, paragraphs, and size in bytes (UTF-8).

Lorem Ipsum Generator

Placeholder text generator — by paragraphs, sentences, or individual words.

Slugify

Convert text to a URL-safe "slug": Cyrillic (uk/ru) transliteration following the official standard, diacritic and punctuation stripping, lowercase.

Markdown Preview / HTML ↔ Markdown

Live preview of Markdown as formatted HTML, plus two-way conversion: Markdown → HTML and HTML → Markdown.

Whitespace & Trim Tools

Clean up excess whitespace: trim line edges, collapse repeated spaces, remove empty lines, convert tabs ↔ spaces.

Text Reverse

Reverse text: by characters, by words (word order), or by lines (line order).

Word/Character Frequency Counter

Frequency analysis of text: how many times each word or character appears, sorted by count.

Hashes/Crypto

Hash Generator

Compute hashes of text or a file with thirteen algorithms at once: MD5, SHA-1, SHA-256, SHA-384, SHA-512, SHA3-256, SHA3-512, RIPEMD-160, BLAKE2b, BLAKE2s, BLAKE3, CRC32, and Adler-32.

Checksum Verifier

Verify the integrity of a file or text — paste the expected hash and the tool will detect the algorithm among 13 supported ones.

HMAC Generator

Compute HMAC (Hash-based Message Authentication Code) of text or a file with a secret key — eight algorithms at once: MD5, SHA-1, SHA-256, SHA-384, SHA-512, SHA3-256, SHA3-512, RIPEMD-160.

Bcrypt Hash + Verify

Hash passwords with bcrypt (random salt, adjustable cost) and verify a password against an existing bcrypt hash.

UUID Generator

Generate UUID versions 1, 3, 4, 5, 6 and 7 — random, time-based, and name-based.

Password Generator

Cryptographically random passwords with configurable length and character set.

AES Encrypt/Decrypt

Encrypt and decrypt text with AES-GCM or AES-CBC using a password (key derived via PBKDF2).

Argon2 Hash + Verify

Hash passwords with Argon2 (winner of the Password Hashing Competition, RFC 9106) — d/i/id variants, with verification against an existing hash.

Scrypt Hash + Verify

Hash passwords with scrypt (RFC 7914, memory-hard KDF), with verification against an existing hash.

TOTP Generator/Verifier

Time-based one-time passwords (TOTP, RFC 6238) — generate the current code from a secret and verify an entered code with clock-drift tolerance.

PBKDF2 Hash + Verify

Derive a key with PBKDF2 (RFC 8018) from a password, HMAC-SHA1/256/384/512, with a configurable iteration count.

X.509 / SSL Certificate Decoder

Decode a PEM certificate (X.509/ASN.1 DER) — subject, issuer, validity, public key, extensions, and fingerprints.

PGP/GPG Encrypt/Decrypt

Generate PGP keys, encrypt and decrypt messages (OpenPGP, RFC 4880) via the openpgp.js library.

Time/Numbers

Unix Timestamp ↔ Date

Convert Unix time to a date and back, with support for arbitrary (IANA) time zones.

Cron Parser

Parse a cron expression (5 or 6 fields, including @-shortcuts) — a plain-language schedule description and next run times in a chosen time zone.

Number Base Converter

Convert between binary, octal, decimal, hexadecimal, and any arbitrary (2-36) base — enter a number into any field.

Bitwise Operations

AND/OR/XOR/NAND/NOR/XNOR/NOT and shifts on integers of a given width (8/16/32/64 bits) in any number base.

Date Diff Calculator

Exact difference between two dates/times — calendar breakdown (years, months, days…), total duration, and business day count.

Age Calculator

Exact age from a birth date — years/months/days, total time lived, and the next birthday.

Timezone Converter

One moment in time, across several time zones at once. Compare working hours, plan calls, see the day difference.

Duration Calculator

Sum or subtract several durations — handy for tallying worked hours, video length, or total task time.

ISO 8601 Duration Parser

Parse a string like "P3Y6M4DT12H30M5S" into a readable breakdown, or build one from years/months/days/hours/minutes/seconds.

Week Number (ISO 8601)

Find the ISO 8601 week number for a date, or find the start/end dates of a specific week.

Roman Numeral Converter

Arabic number ↔ Roman numeral. Type into either field and the other updates automatically.

IEEE 754 Float Converter

Decimal number ↔ IEEE 754 binary representation (single or double precision) — sign, exponent, mantissa, special values.

Number to Words

Convert a number into text (in Ukrainian, Russian, or English), with an optional currency-amount mode for hryvnia, dollar, euro, or ruble.

Web Development

Color Converter

Convert colors between HEX, RGB, HSL, HSV/HSB, and CMYK — enter a value into any field and the rest update instantly.

CSS Minify / Beautify

Compress CSS for production, or format minified CSS into a readable layout.

JS Minify / Beautify

Compress JavaScript for production, or format minified code into a readable layout.

HTML Minify / Beautify

Compress HTML for production, or format minified markup into a readable layout.

CSS Gradient Generator

Build a linear, radial, or conic gradient from multiple colors and get ready-to-use CSS.

Credit Card Validator

Validate a card number with the Luhn algorithm, detect the payment network and length. Everything runs in the browser — the number is never sent anywhere.

IBAN Validator

Validate an IBAN against the ISO 7064 (mod 97) checksum, format, and the expected length for its country. Everything runs in the browser.

QR Code Generator / Reader

Generate a QR code from text or a URL, or read the content of an uploaded QR code image.

Barcode Generator

Generate a linear barcode (CODE128, EAN-13, UPC, CODE39, and others) from text or digits.

Placeholder Image Generator

Generate a placeholder image of a given size for mockups and layout.

Network/HTTP

URL Parser

Break a URL down into its parts — protocol, host, port, path, query parameters, fragment.

Query String ↔ JSON

Parse a URL query string into a JSON object, or build a query string back from JSON.

User-Agent Parser

Break a User-Agent string down into browser, engine, operating system, and device type.

Basic Auth Generator

Generate or decode an HTTP Basic Authentication header — Base64(username:password).

HTTP Headers Parser

Parse raw HTTP headers (from curl -I, DevTools, raw response) into a field list with descriptions and a security headers check.

Cookie Parser

Parse a Set-Cookie header or a Cookie/document.cookie string into name, value, attributes, and a check for common security mistakes.

CORS Checker / Explainer

Explain step by step whether the browser will allow a cross-origin request — simple/preflight classification, Access-Control-* response header checks, and a verdict.

Email Header Analyzer

Parse raw email headers (View Source / Show Original) — key fields, the Received chain with hop timings, SPF/DKIM/DMARC, From/Reply-To spoofing indicators.

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