One toolbox.
30 essential developer tools.
Encode, decode, format, convert, generate and inspect — right in your browser. No sign-up, no uploads, nothing sent to a server. Works on mobile, dark mode included.
Encode & Decode
5 toolsBase64 Encoder / Decoder
Encode text to Base64 or decode it back in one click, plus image ⇄ Base64 data-URL conversion with drag & drop. Free, instant and 100% browser-based — nothing is uploaded.
Open tool →URL Encoder / Decoder
Percent-encode or decode URLs and query components instantly. Component or full-URL mode, live size stats, strict position-accurate error reporting — all offline in your browser.
Open tool →HTML Entity Encoder / Decoder
Convert special characters to HTML entities (& < > …) or decode named and numeric entities back to text. Safe, instant and entirely client-side.
Open tool →Unicode Converter
Convert any text to \uXXXX JavaScript escapes, U+XXXX code-point lists, 0x hex or numeric entities — and paste escapes back to readable text. Emoji and surrogate pairs handled correctly.
Open tool →Hex to Text Converter
Convert text to hexadecimal (UTF-8) and decode hex strings back to readable text. Tolerates 0x prefixes, colons and spaces — with strict position-aware error messages.
Open tool →JSON & Data
9 toolsJSON Formatter
Pretty-print JSON with 2/4-space or tab indentation, optional key sorting, and precise error positions when the JSON is broken. Private, instant, browser-only.
Open tool →JSON Validator
Validate JSON instantly and get the exact line, column and nearby snippet of any syntax error. Valid input shows structure stats: root type, keys, depth and size.
Open tool →JSON Minifier
Minify JSON to a single line by stripping all insignificant whitespace. See original vs minified size and exactly how many bytes you saved. Fully offline.
Open tool →JSON to CSV
Convert a JSON array of objects into properly quoted CSV with your choice of delimiter. Non-flat values are serialized to embedded JSON text. Downloads and copies in one click.
Open tool →CSV to JSON
Convert CSV (with quoted fields, embedded commas and line breaks) to a JSON array of objects. Optional auto-conversion of numbers and booleans. One-click copy or download.
Open tool →XML Formatter
Pretty-print messy XML with proper indentation, or minify it to a single line. Attributes, comments and text nodes are handled safely, with parse errors explained.
Open tool →YAML to JSON
Convert YAML to JSON right in the browser. Supports nested maps, lists, quoted strings, numbers, booleans and inline arrays — with helpful indentation errors.
Open tool →JSON to TypeScript
Paste JSON and get ready-to-use TypeScript interfaces: nested objects become interfaces, arrays infer element types, keys are PascalCased, invalid keys quoted. Instant and offline.
Open tool →URL Parser
Paste any URL and see protocol, host, port, path, hash and every query parameter in a clean table. Relative URLs are resolved against a configurable base. Nothing is sent anywhere.
Open tool →Text Tools
5 toolsText Diff Checker
Compare two texts and see added, removed and unchanged lines with an LCS diff algorithm. Colors, counters and a line-by-line unified view — computed locally.
Open tool →Text Deduplicator
Remove duplicate lines from any list with options for trimming whitespace, ignoring case and dropping empty lines. Shows before/after counts and what was removed.
Open tool →Word Counter
Live word, character, sentence and paragraph statistics plus reading-time estimates. Works offline on any text — no length limits, nothing uploaded.
Open tool →Case Converter
Convert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case or CONSTANT_CASE in one glance, each with its own copy button.
Open tool →Regex Tester
Test regular expressions against sample text with live match highlighting, capture-group tables and match counters. Flags toggle instantly. Errors explain what broke.
Open tool →Converters
6 toolsNumber Base Converter
Convert integers between binary, octal, decimal, hexadecimal and any custom base 2–36 using BigInt — so arbitrarily large numbers stay exact. Invalid digits are pinpointed.
Open tool →Color Converter
Convert colors between HEX, RGB/RGBA and HSL/HSLA with a live swatch preview. Paste any common CSS color format and get all equivalents plus copyable strings.
Open tool →Unix Timestamp Converter
Convert Unix timestamps (seconds or milliseconds) to human dates in local time, UTC and ISO — and dates back to epoch seconds. Copyable, live “now” button.
Open tool →Cron Expression Parser
Parse a 5-field cron expression into plain English, validate every field, and preview the next scheduled run times. All offline — supports *, ranges, steps and lists.
Open tool →Markdown Previewer
Type Markdown on the left, see the rendered preview on the right — headings, lists, links, code blocks, quotes and emphasis. XSS-safe: everything is escaped first.
Open tool →CSS Formatter / Minifier
Beautify CSS with consistent indentation and one-declaration-per-line, or minify it by stripping comments and whitespace. Handles media queries and nested braces.
Open tool →Crypto & Security
4 toolsJWT Decoder
Decode a JWT header and payload into readable JSON with formatted dates for exp/iat/nbf, signature state and expiry status. Safe: verification never happens in the browser.
Open tool →UUID Generator
Generate UUID v4 identifiers using the browser crypto RNG — crypto.randomUUID where available, a vetted fallback elsewhere. Bulk batches, optional uppercase, custom dash style.
Open tool →Password Generator
Generate cryptographically strong passwords with adjustable length and character sets, ambiguous-character filter and entropy readout. Five candidates at a time, 100% offline.
Open tool →SHA-256 Generator
Compute the SHA-256 digest of any text instantly — with SHA-1, SHA-384 and SHA-512 alongside. Uses WebCrypto when available, with a pure-JS fallback. Includes HMAC demo mode.
Open tool →Generate & Media
1 toolsGuides & articles
20 guidesBase64 vs Hex Encoding: When to Use Each (Developer Guide)
Base64 vs hex encoding compared: size overhead, readability, common use cases in JWTs, data URLs and git diffs — with a quick decision table for engineers.
Read guide →2026-10-11How to Decode a JWT: Reading Header, Payload and Signature
Decode any JWT by hand or with a browser tool: how the three parts are encoded, which claims matter (sub, exp, iss, aud) and why decoding is not verification.
Read guide →2026-10-10UTF-8 Explained: Why One Chinese Character Counts as 3 Bytes
How UTF-8 encodes ASCII, Latin accents, CJK and emoji: byte lengths per code point, why string length disagrees across systems and how to inspect any character.
Read guide →2026-10-09Cron Expressions: A Field-by-Field Guide with Real Examples
Read and write cron like a native: what the 5 fields mean, steps and ranges, the day-of-month vs day-of-week rule, @daily shorthands and timezone pitfalls.
Read guide →2026-10-07UUID v4 and v7: The Complete Guide for Databases and APIs
What a UUID actually encodes, v4 vs v7 trade-offs for database indexes, how unique is truly unique, and why UUIDs are not secrets.
Read guide →2026-10-06Why Your JSON Is Invalid: The 9 Most Common Syntax Errors
Trailing commas, unquoted keys, smart quotes and friends: the nine JSON syntax mistakes that break parsers, with instant fixes and a validation shortcut.
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