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Friday, August 21

Developer Tools

Free browser-based developer tools on Justwebworld. Everything runs locally in your browser — pasted data is never uploaded or stored.

JSON Tools

  • JSON Structure Compare

    Paste two JSON documents to compare their structure — keys and value types — while ignoring the actual values.

  • JSON Flattener

    Convert nested JSON into a flat, single-level object whose keys are the full paths (for example user.

  • JSON Unflattener

    Rebuild nested JSON from a flat object whose keys are paths (user.

  • JSON Key Extractor

    List every key in a JSON document — as unique key names or as full JSONPath key paths — with optional counts and sorting.

  • JSON Empty Value Remover

    Strip null values, empty strings, empty objects and empty arrays from JSON — you choose which.

  • JSONPath Finder

    Paste JSON and get the JSONPath expression of every element — browse the interactive tree or the full path list, click any node to copy its path.

  • JSON String Escape / Unescape

    Escape raw text into JSON string content — or unescape a JSON string back to readable text.

  • JSON Formatter

    Pretty-print JSON with your choice of 2-space, 4-space or tab indentation, with optional alphabetical key sorting.

  • JSON Validator

    Check whether text is valid JSON per RFC 8259.

  • JSON Minifier

    Strip all unnecessary whitespace from JSON to its smallest valid form — with an exact before/after size comparison.

  • JSON Viewer

    Explore JSON in a collapsible interactive tree with a type badge on every node — click any value to copy it.

  • JSON Sorter

    Sort JSON object keys alphabetically (recursively), sort array values, or both — ascending or descending, with object arrays sortable by any key.

  • JSON Size Calculator

    Measure a JSON payload: UTF-8 bytes as pasted, minified and formatted, plus structure stats (depth, keys, items) and a ranking of the heaviest top-level members.

  • JSON Duplicate Key Finder

    Find keys defined more than once in the same object — the values your JSON parser silently throws away.

  • JSON Key Renamer

    Rename a key everywhere it appears in a JSON document — at any depth, inside arrays too — with an occurrence count and overwrite warnings.

  • JSON Property Remover

    Delete properties from JSON by name — a comma-separated list, removed at every depth.

  • JSON Array to Object Converter

    Turn a JSON array into an object — keyed by any property of the elements (id, slug, name) for O(1) lookups, or by numeric index.

  • JSON Object to Array Converter

    Turn a JSON object into an array — value objects with the key merged in, {key, value} pairs, or plain values.

  • JSON Compare

    Compare two JSON documents value by value: every added, removed and changed value reported with its JSONPath and before/after.

  • JSONPath Tester

    Evaluate a JSONPath expression against your JSON and see exactly what it matches — values and paths.

  • JSON Query Filter

    Filter a JSON array of records by a field condition — equals, contains, greater/less than, exists — without learning a query language.

  • JSON Merge

    Merge two JSON documents — deep recursive merge with array strategies (replace, concat, unique), shallow merge, or RFC 7386 JSON Merge Patch where null deletes a key.

  • JSON Patch Generator

    Generate an RFC 6902 JSON Patch — the add/remove/replace operations that transform document A into document B — ready for HTTP PATCH requests and audit logs.

  • JSON Patch Applier

    Apply an RFC 6902 JSON Patch to a document — all six operations (add, remove, replace, move, copy, test), executed in order with test-failure abort, exactly per the spec.

JSON Schema Tools

  • JSON to JSON Schema Converter

    Generate a JSON Schema (draft 2020-12) from an example JSON document.

  • JSON Schema Example Generator

    Generate a sample JSON document from a JSON Schema — honoring const, default, enum, formats, required properties and local $refs.

  • JSON Schema Validator

    Validate a JSON document against a JSON Schema (draft 2020-12 subset): types, required properties, enums, formats, constraints, allOf/anyOf/oneOf and local $refs — every violation listed with its location.

  • JSON Schema Compare

    Compare two versions of a JSON Schema and see what changed for API consumers — removed properties and type changes flagged as breaking, new requirements as warnings, additions as informational.

Data Converters

  • JSON to TypeScript Converter

    Turn a JSON example into TypeScript interfaces — nested objects become named interfaces, arrays of objects merge with optional keys, and mixed types become unions.

  • JSON to Markdown Table Converter

    Convert a JSON array of objects into a Markdown table — one row per element, columns from the union of keys, pipes and line breaks escaped.

  • JSON to YAML Converter

    Convert JSON to clean YAML — for Kubernetes manifests, CI pipelines, docker-compose and config files.

  • YAML to JSON Converter

    Convert YAML to JSON with a safe parser — anchors and merge keys expanded, no code execution, errors reported with line and column.

  • JSON to XML Converter

    Convert JSON to XML — objects become elements, arrays repeat a singularized child element, and special characters are escaped.

  • XML to JSON Converter

    Convert XML to JSON — attributes become "@" keys, repeated elements become arrays, and numeric or boolean text optionally becomes real types.

  • JSON to CSV Converter

    Convert a JSON array of objects to CSV for Excel and Google Sheets — RFC 4180 quoting, nested objects flattened into dotted columns, comma/semicolon/tab delimiters.

  • JSON to JavaScript Object Converter

    Convert JSON into a JavaScript object literal — identifier keys unquoted, your choice of quote style, optional trailing commas and declaration prefix.

  • JSON to PHP Array Converter

    Convert JSON into a PHP array literal — short [] or array() syntax, single-quoted escaped strings, the exact structure json_decode($json, true) would produce.

  • JSON to Python Dictionary Converter

    Convert JSON into a Python dict literal — true/false/null become True/False/None, strings are escaped for Python, and the result is valid Python 3 as-is.

  • JSON to Java Class Converter

    Generate Java classes from a JSON example — POJOs with getters/setters, Java 16+ records, or Lombok style.

  • JSON to C# Class Converter

    Generate C# classes or records from a JSON example — PascalCase properties with [JsonPropertyName] attributes for System.

  • JSON to SQL Insert Converter

    Convert a JSON array of objects into SQL INSERT statements — MySQL, PostgreSQL/ANSI or SQL Server quoting, multi-row or per-row, nested objects flattened into columns.

  • JSON to HTML Table Converter

    Convert a JSON array of objects into a semantic HTML table — thead/tbody, scoped headers, optional caption and CSS class, with every value HTML-escaped for safety.

  • JSON to URL Parameters Converter

    Convert a JSON object into a URL query string — percent-encoded, with nested keys in bracket (PHP/Rails) or dot style, and null handling you control.

Tailwind Css Tools

  • Tailwind Color Palette Generator

    Turn one brand color into a complete Tailwind-style 50–950 shade palette, generated perceptually in OKLCH — exported as v3 config, v4 @theme, CSS variables or JSON.

  • Tailwind v3 to v4 Converter

    Migrate Tailwind v3 code toward v4: rename utilities per the official upgrade guide (shadow-sm→shadow-xs, ring→ring-3, outline-none→outline-hidden…) and convert theme config objects into v4 @theme CSS.

  • Tailwind Theme Generator (v3 config + v4 @theme)

    Build a complete Tailwind theme starter — primary and secondary color scales, font stack and radius scale — exported as a v4 @theme block or a v3 tailwind.

  • Tailwind Class Validator

    Check a class list or markup for typos: every class is tested against Tailwind's core utility grammar, with unknown classes, bad variants and arbitrary values reported separately.

  • Tailwind Class Cleaner

    Clean a Tailwind class list: exact duplicates removed and conflicting utilities (two paddings, two display modes, two text colors) resolved last-wins — with a report of everything removed.

  • Tailwind Animation Generator

    Build custom Tailwind animations — fade, slide, zoom, wiggle, float, shake — with duration and easing controls, a live replayable preview, and v3 config, v4 @theme or plain CSS output.

  • Tailwind Gradient Generator

    Build Tailwind gradients visually — direction, two or three color stops — and copy the classes in v4 (bg-linear-to-*) or v3 (bg-gradient-to-*) form, or as plain CSS.

  • Tailwind Opacity Generator

    Combine any color with any opacity using Tailwind's slash modifier (bg-blue-500/50) — previewed over a checkerboard, with the plain-CSS equivalent and the deprecated legacy pattern explained.

  • Tailwind Spacing Generator

    Generate a custom Tailwind spacing scale from your own base unit — visualized as proportional bars, exported as v3 config, the v4 –spacing variable, or CSS custom properties.

  • Tailwind Border Radius Generator

    Set each corner's radius with sliders and get the matching Tailwind classes — core rounded-* names when values sit on the scale, arbitrary values when they don't — plus plain CSS.

  • Tailwind Box Shadow Generator

    Design a custom shadow with offset, blur, spread, color and opacity sliders — exported as a Tailwind arbitrary class, a named v4 @theme or v3 config token, or plain CSS.

  • Tailwind Typography Generator

    Generate a modular Tailwind font-size scale — base size × musical ratio, with line heights paired automatically — as v4 @theme, v3 fontSize config or CSS variables.

  • Tailwind Grid Generator

    Build a Tailwind CSS grid visually — columns, rows, gap and a mobile-first responsive pattern (grid-cols-1 sm:grid-cols-2 lg:grid-cols-N) — with the markup ready to copy.

  • Tailwind Flexbox Generator

    Compose Tailwind flexbox layouts visually — direction, justify, align, wrap and gap — watching items rearrange live, then copy the classes or the CSS equivalent.

  • Tailwind Breakpoint Generator

    Define custom Tailwind breakpoints as name:pixel pairs — visualized to scale, exported as v4 –breakpoint-* variables, a v3 screens config, or raw media queries.

  • Tailwind Button Generator

    Generate accessible Tailwind buttons — solid, outline or ghost, in three sizes — with hover shades derived from your brand color and a visible focus ring included by default.

  • Tailwind Card Generator

    Compose a Tailwind card — padding, radius, shadow, border, hover lift and optional dark: variants — previewed live with real content structure, ready to paste.

  • Tailwind Form Generator

    Generate accessible Tailwind form markup — labeled inputs, select, textarea, consent checkbox, focus rings and an aria-wired error-state pattern — the boilerplate done right once.

  • CSS to Tailwind Converter

    Translate CSS declarations into Tailwind utilities — scale values map to core classes, off-scale values become arbitrary values, near-miss colors map to the closest palette color.

  • Tailwind to CSS Converter

    See exactly what CSS a Tailwind class list generates — core utilities translated to their v3.

  • HEX to Tailwind Color

    Find the Tailwind palette color closest to any hex value — top five matches ranked by perceptual OKLab distance, with side-by-side swatches and an honest "keep your exact color" fallback.

  • Tailwind Class Sorter

    Sort Tailwind classes into the conventional order — layout → flex/grid → spacing → sizing → typography → visual → effects, base classes before variants — approximating the official Prettier plugin.

Css Tools

  • CSS Clip-Path Generator

    Clip elements into triangles, hexagons, stars, arrows, message bubbles and more — pick a shape, tune it, and copy the clip-path CSS or the Tailwind arbitrary-value class.

  • CSS Gradient Generator

    Build linear, radial and conic CSS gradients visually — angle or center position, two or three stops with positions — and copy the background-image declaration.

  • CSS Box Shadow Generator

    Generate layered CSS box-shadows — up to six stacked layers with quadratic falloff, the technique that makes depth look natural instead of flat — tuned with sliders.

  • CSS Border Generator

    Compose CSS borders per side — width, all eight border styles, color and radius — with live preview and honest notes on which styles still earn their place in modern UI.

  • CSS Border Radius Generator

    Shape corners with the full 8-value border-radius syntax — separate horizontal and vertical radii per corner — for organic blobs, eggs and leaves no 4-value radius can make.

  • CSS Transform Generator

    Combine translate, rotate, scale and skew with sliders — order preserved, transform-origin selectable — and copy the composed transform declaration.

  • CSS Filter Generator

    Stack CSS filters — blur, brightness, contrast, saturation, grayscale, sepia, hue-rotate, invert — with a before/after preview and the composed filter declaration.

  • CSS Animation Generator

    Generate complete CSS animations — ten entrance/attention presets with duration, delay, easing (including a spring overshoot) — as an @keyframes block plus the animation shorthand, reduced-motion handled.

  • CSS Grid Generator

    Generate CSS Grid layouts — equal columns, the auto-fit responsive pattern that needs no media queries, or a full page layout with named grid areas — previewed live.

  • CSS Flexbox Generator

    Learn and generate flexbox by watching it: direction, justify-content, align-items, wrap and gap with live items — plus the flex:1 per-item pattern — copied as CSS.

  • CSS Glassmorphism Generator

    Create the frosted-glass effect — backdrop-filter blur and saturation, translucent tint, glowing border — tuned over a colorful demo scene so you see the real result.

  • CSS Neumorphism Generator

    Generate soft-UI (neumorphism) styles — flat, pressed, convex or concave — with the light and dark shadows derived from your surface color in OKLCH so the illusion holds.

  • CSS Text Shadow Generator

    Style text shadows four ways — subtle depth, neon glow, sticker outline and retro 3D stacking — previewed on your own text with the composed declaration ready to copy.

  • CSS Loader Generator

    Generate CSS-only loading spinners — ring, dual ring, bouncing dots, equalizer bars, pulse — with size, color and speed controls, accessible markup and reduced-motion fallbacks.

Design Token Tools

  • OKLCH Color Generator

    Mix colors directly in OKLCH with lightness, chroma and hue sliders — live preview, sRGB gamut warnings, and CSS output with hex/rgb/hsl fallbacks.

  • HEX to OKLCH Converter

    Convert hex, rgb() or hsl() colors to oklch() — one per line, batch-friendly, computed per CSS Color Module Level 4 with the original kept as a comment.

  • Design Token Generator

    Generate a coherent starter token system — two color scales, spacing, radius and a modular type scale — exported as CSS variables, SCSS, Tailwind v4 @theme, JSON or DTCG draft tokens.

  • Semantic Color Token Generator

    Turn five brand colors into semantic tokens — primary, success, warning, danger, info — each with hover, active, subtle, border, strong and on-color slots, ready for CSS or Tailwind v4.

  • Light/Dark Theme Generator

    Generate coordinated light and dark theme tokens from one brand color — with your choice of dark-mode strategy: .

  • Figma Token JSON Generator

    Generate design-token JSON for Figma workflows — Tokens Studio plugin format and the W3C DTCG draft format — from a brand color, with radius and spacing tokens included.

  • CSS Variables Generator

    Turn name:value pairs into a clean :root custom-property block — names normalized to kebab-case, with usage examples for CSS and JavaScript and an optional dark-mode override skeleton.

  • SCSS Variables Generator

    Turn name:value pairs into SCSS — plain $variables, or a Sass map with a safe token() getter that errors on unknown names — with !default for library authors.

Accessibility Color Tools

  • WCAG Contrast Checker

    Check any text/background color pair against WCAG 2.

  • Accessible Text Color Generator

    Pick a background and get text colors that actually pass WCAG — black, white and same-hue tints ranked by real contrast ratio, with AA/AAA marked on each.

Base Encoding Tools

  • Base64 Encoder

    Convert text or Unicode characters into Base64 – the binary-to-text encoding used by email attachments, data URIs and HTTP basic authentication.

  • Base64 Decoder

    Decode a Base64 string back to readable text, with clear errors for invalid characters, wrong length and bad padding.

  • Base64URL Encoder

    Encode text with the URL-safe Base64 alphabet from RFC 4648 section 5: minus and underscore replace plus and slash, and padding is normally dropped, so the result is safe in URLs, filenames and JWTs.

  • Base64URL Decoder

    Decode URL-safe Base64 – the variant used in JWT header and payload sections – back to text, handling missing padding automatically.

  • Base32 Encoder

    Encode data as Base32 (RFC 4648) using the case-insensitive A-Z 2-7 alphabet found in TOTP authenticator secrets, DNS records and Onion addresses.

  • Base32 Decoder

    Decode Base32 back to text or bytes.

  • Base58 Encoder

    Encode bytes as Base58 – the Bitcoin alphabet that deliberately omits 0, O, I and l so codes survive being read aloud, handwritten or retyped.

  • Base58 Decoder

    Decode a Base58 string such as a Bitcoin address or IPFS CIDv0 back to its underlying bytes, shown as text where possible and hex otherwise.

  • Ascii85 Encoder

    Encode data as Ascii85 (base85), which packs 4 bytes into 5 characters for about 25 percent overhead versus the 33 percent of Base64.

  • Ascii85 Decoder

    Decode Ascii85 or base85 data back to bytes, accepting the Adobe delimiters and the z shortcut that stands for four zero bytes.

URL and Web Encoding Tools

  • URL Encoder

    Percent-encode a URL or a single value.

  • URL Decoder

    Decode percent-encoded URLs back to readable text, with an optional plus-as-space rule and a repeat mode that unwraps double-encoded values such as %253A.

  • URI Component Encoder

    Escape a single URI component – a query value, path segment or fragment – so reserved characters like ampersand, equals, question mark, slash and hash cannot break the surrounding URL.

  • URI Component Decoder

    Decode a single percent-encoded URI component back to its original value, treating the plus sign as a space by default as HTML form submissions do.

  • Query String Parser

    Split a URL query string into readable key and value pairs or JSON, decoding percent-escapes and plus signs, and flagging repeated parameters whose handling differs between servers.

  • Query String Builder

    Turn key and value lines or a JSON object into a correctly escaped query string, with repeated keys for array values and optional RFC 3986 strict escaping.

  • HTML Entity Encoder

    Convert characters into HTML entities so markup displays as text instead of being parsed.

  • HTML Entity Decoder

    Turn HTML entities back into characters – named, decimal and hexadecimal – with a repeat mode for text that was escaped twice.

  • XML Entity Encoder

    Escape text for XML, which predefines only amp, lt, gt, quot and apos – everything else must be a numeric reference.

  • XML Entity Decoder

    Decode XML entities back to text.

  • Punycode Encoder

    Convert an internationalized domain name to its ASCII xn-- form using RFC 3492 Punycode, so non-Latin domains work in DNS.

  • Punycode Decoder

    Turn xn-- domain labels back into readable Unicode, and flag mixed-script labels that may be homograph lookalike domains used in phishing.

Text and Character Encoding Tools

  • Text to Binary

    Convert text into binary – eight bits per UTF-8 byte, or one number per Unicode code point.

  • Binary to Text

    Convert binary numbers back into readable text.

  • Text to Hex

    Convert text to hexadecimal – two hex digits per UTF-8 byte, or per code point.

  • Hex to Text

    Convert hexadecimal back to text, accepting spaces, commas, colons and 0x prefixes, and warning when the bytes decode to something other than clean UTF-8.

  • Text to ASCII

    Convert text to ASCII character codes in decimal, hex, binary or octal, with strict validation because ASCII defines only the 128 characters numbered 0 to 127.

  • ASCII to Text

    Turn ASCII character codes back into text, with an option to name control characters such as LF and TAB instead of printing invisible bytes.

  • Text to Decimal

    Convert text into decimal numbers – full Unicode code points by default, so an emoji becomes a single number such as 128512 rather than several byte fragments.

  • Decimal to Text

    Convert decimal numbers back into characters, treating them as Unicode code points or as raw UTF-8 bytes, with clear errors for surrogates and out-of-range values.

  • Text to Octal

    Convert text into octal, base 8, at three digits per byte.

  • Octal to Text

    Convert octal numbers back into readable text, validating that every digit falls in the range 0 to 7.

  • Unicode Escape

    Turn characters into escape sequences for JavaScript, ES6, CSS, Python, Java or C, which is useful when source files or config formats must stay pure ASCII.

  • Unicode Unescape

    Convert escape sequences in the JavaScript, ES6, Python and hex styles back into the characters they represent, flagging unpaired surrogates.

  • Unicode Code Point Converter

    Look up the code point of every character – with its decimal value, UTF-8 bytes and UTF-16 units – or turn U+ notation back into text.

  • UTF-8 Encoder and Decoder

    Inspect exactly how text becomes UTF-8 bytes – as hex, percent-escapes, decimal or hex escapes – and convert those bytes back to text.

  • UTF-8 Byte Counter

    Count UTF-8 bytes, characters and UTF-16 units separately – the three numbers that disagree whenever emoji or non-Latin scripts appear – and compare them against common limits.

  • Character Encoding Detector

    Analyse bytes for a byte order mark, ASCII-only content, valid UTF-8 and classic mojibake patterns, separating what can be proven from what can only be guessed.

Cipher and Communication Tools

  • ROT13 Encoder and Decoder

    Apply ROT13, ROT13.

  • Caesar Cipher Encoder and Decoder

    Shift letters by any amount from 1 to 25, or break an unknown Caesar cipher instantly by showing all 25 possible shifts at once.

  • Atbash Cipher

    Apply the Atbash substitution, which mirrors the alphabet so A becomes Z and B becomes Y.

  • Vigenere Cipher Encoder and Decoder

    Encrypt or decrypt with a repeating keyword, the classic polyalphabetic cipher.

  • Morse Code Translator

    Translate text to international Morse code and back, covering letters, digits and common punctuation, with configurable word separators.

  • NATO Phonetic Alphabet Converter

    Spell text out in the ICAO and NATO phonetic alphabet – Alfa, Bravo, Charlie – for reading codes aloud over phone or radio, and convert phonetic words back to text.

  • Quoted-Printable Encoder

    Encode text as quoted-printable (RFC 2045), the email transfer encoding that keeps mostly-ASCII text readable while escaping everything else.

  • Quoted-Printable Decoder

    Decode a quoted-printable email body back to readable text, resolving the escapes and removing soft line breaks.

  • MIME Header Encoder and Decoder

    Decode encoded words from email Subject and From headers, or build your own – the RFC 2047 mechanism that lets ASCII-only headers carry any language.

JWT and Token Tools

  • JWT Decoder

    Decode a JSON Web Token to inspect its header and payload, with registered claims explained and timestamps converted to dates.

  • JWT Structure Validator

    Check a JWT for structural problems – section count, Base64URL validity, JSON shape, the required alg field, claim types, expiry and the dangerous alg none case.

  • JWT Encoder

    Build and sign a demonstration JWT locally with HS256, HS384 or HS512.

General Base Converters

  • Number System Converter

    Convert any number into binary, octal, decimal, hexadecimal and a custom base of your choice at the same time – with exact BigInt arithmetic, so even very large values never lose precision.

  • Any Base Converter

    Convert a number between any two bases from 2 to 36 – binary, ternary, octal, decimal, hex, base 32, base 36 and everything in between – exactly, with no size limit.

  • Base 2 to 62 Converter

    Convert numbers in any base up to 62, where digits are case-sensitive: 0-9, then A-Z for 10-35, then a-z for 36-61.

  • Fractional Base Converter

    Convert numbers WITH a fractional part between any bases 2-36, using exact fraction arithmetic that detects repeating digits instead of silently rounding them.

Binary and Decimal

Binary and Hex

  • Binary to Hex Converter

    Convert binary to hexadecimal by splitting the bits into 4-bit groups (nibbles) – each group maps to exactly one hex digit.

  • Hex to Binary Converter

    Convert hexadecimal to binary by expanding every hex digit into its 4-bit pattern.

Binary and Octal

Decimal and Hex

  • Decimal to Hex Converter

    Convert a decimal number to hexadecimal by repeated division by 16 – remainders above 9 become the letters A-F.

  • Hex to Decimal Converter

    Convert hexadecimal to decimal by summing place values – each digit is multiplied by a power of 16, with A-F standing for 10-15.

  • Hex Fraction to Decimal Converter

    Convert a hexadecimal number with a fractional part (such as A.

  • Decimal Fraction to Hex Converter

    Convert a decimal fraction to hexadecimal by repeated multiplication by 16, with exact detection of repeating hex digits – the float notation used in some language literals.

Decimal and Octal

Hex and Octal

  • Hex to Octal Converter

    Convert hexadecimal to octal via binary: each hex digit becomes 4 bits, and the bits regroup into 3-bit octal digits.

  • Octal to Hex Converter

    Convert octal to hexadecimal via binary: 3-bit octal groups merge into 4-bit hex nibbles.

Signed Number Tools

Digital Electronics Tools

  • Binary to Gray Code Converter

    Convert weighted binary to reflected Gray code with g = b XOR (b >> 1) – in a Gray sequence, consecutive values differ in exactly one bit, which kills glitches in rotary encoders.

  • Gray Code to Binary Converter

    Convert reflected Gray code back to weighted binary by cascading XOR from the top bit down – each binary bit is the XOR of the previous binary bit with the current Gray bit.

  • Decimal to Gray Code Converter

    Convert a decimal number straight to Gray code – first to binary, then one XOR pass.

  • Gray Code Table Generator

    Generate the full decimal-binary-Gray table for 2 to 6 bits.

  • BCD to Decimal Converter

    Decode binary-coded decimal: each 4-bit group is one decimal digit 0-9.

  • Decimal to BCD Converter

    Encode a decimal number as BCD – each digit becomes its own 4-bit group, so 429 becomes 0100 0010 1001.

  • Excess-3 Code Converter

    Convert between decimal and Excess-3 code, where each digit is stored as digit + 3 in four bits – a self-complementing code from the era of decimal arithmetic hardware.

Number System Calculators

  • Binary Calculator

    Add, subtract, multiply or divide two binary numbers with exact BigInt arithmetic – the addition mode traces every column and carry for your actual operands.

  • Binary Addition Calculator

    Add two binary numbers with a full column-by-column carry trace – see exactly where 1+1 writes 0 and carries 1, for your actual inputs.

  • Binary Subtraction Calculator

    Subtract one binary number from another exactly, including negative results – and see why hardware actually subtracts by adding the two’s complement.

  • Binary Multiplication Calculator

    Multiply two binary numbers exactly, at any length.

  • Binary Division Calculator

    Divide two binary numbers exactly, returning the integer quotient and the remainder separately – the form long division and hardware dividers actually produce.

  • Hex Calculator

    Add, subtract, multiply or divide hexadecimal numbers exactly – with a decimal cross-check in the result so you can verify at a glance.

  • Hex Addition Calculator

    Add two hexadecimal numbers exactly – columns carry at 16, so 8 + 9 writes 1 and carries 1, and the decimal cross-check confirms the result.

  • Hex Subtraction Calculator

    Subtract hexadecimal numbers exactly, including negative results – with borrows worth 16 rather than 10, which is where hand calculations usually slip.

  • Hex Multiplication Calculator

    Multiply hexadecimal numbers of any size exactly.

  • Hex Division Calculator

    Divide hexadecimal numbers exactly, returning quotient and remainder in hex with a decimal cross-check – useful for address arithmetic and alignment calculations.

  • Octal Calculator

    Add, subtract, multiply or divide octal numbers exactly – carries and borrows happen at 8, and the decimal equivalents are shown so every step can be checked.

  • Base-N Calculator

    Do exact arithmetic in ANY base from 2 to 36 – pick the base, pick the operation, and get the result in that base with a decimal cross-check.

  • Binary Bit Shift Calculator

    Shift a value left or right and see the bits move – logical shifts insert zeros, arithmetic right shift copies the sign bit, and every shift is a multiply or divide by two.

  • Binary Bitmask Calculator

    Apply AND, OR, XOR and AND-NOT between a value and a mask, bit by bit – the four operations behind testing, setting, toggling and clearing flags.

How these tools work

Every tool in this collection processes data locally in your browser with JavaScript. Nothing you paste is transmitted, logged or stored — which matters, because developer data routinely contains API keys, customer records and internal URLs. There are no accounts, no usage caps and no watermarks.

Built as workflows, not one-offs

The tools chain deliberately. Flatten a nested payload, remove its empty values, then publish it as a Markdown table. Generate a schema from a sample response, then generate fresh examples from that schema for your tests. Each tool page links its previous and next step, so a multi-step job never dead-ends.

This cluster starts with JSON — the format nearly every API speaks — and grows from here. Missing a tool you need? Tell us and it goes on the roadmap.

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Michael Austin is the current owner of Justwebworld and manages the platform’s editorial direction, content strategy, and digital publishing operations. With a strong interest in online media and modern publishing, he focuses on creating informative, engaging, and easy-to-understand content across multiple categories.Under his leadership, Justwebworld continues to grow as a trusted multi-niche digital publication covering technology, business, lifestyle, automotive, sports, travel, and trending internet topics for readers worldwide.

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