All tools.

Format and beautify JSON data with syntax highlighting and collapsible tree view.

Minify and compress JSON by removing all whitespace.

Validate JSON syntax and get descriptive error messages with line numbers.

Compare two JSON objects and visualize the differences.

Convert JSON data to YAML format instantly.

Convert JSON arrays to CSV format, ready to open in Excel.

Generate TypeScript interfaces and types from JSON data.

Generate Go struct definitions from JSON data.

Test JSONPath expressions against JSON data and see results instantly.

Generate a JSON Schema from any JSON document automatically.

Generate Python TypedDict or dataclass definitions from JSON data.

Generate Rust structs with serde derive attributes from JSON data.

Generate Kotlin data classes with Gson annotations from JSON data.

Generate Swift Codable structs from JSON data.

Generate C# records or classes with JsonPropertyName attributes from JSON data.

Generate Dart classes with fromJson/toJson helpers from JSON data.

Generate Zod validation schemas and TypeScript types from JSON data.

Generate Java records with Jackson annotations from JSON data.

Generate PHP 8+ typed classes with fromArray hydration from JSON data.

Generate Yup validation schemas from JSON data.

Generate an OpenAPI Schema Object from JSON data.

Generate a MySQL CREATE TABLE statement from JSON data.

Convert JSON data to XML markup with configurable root and pretty-printing.

Convert JSON data to INI configuration file format.

Convert JSON data to .env / properties style KEY=value lines.

Convert JSON data to TOML configuration format.

Interactive collapsible tree view for exploring and navigating JSON data.

Convert a JSON array into a sortable, searchable HTML table.

Generate GraphQL type definitions from a JSON object's structure.

Compare two JSON documents and see every added, removed, and changed value, with the full key path to each difference.

Convert a JSON sample into Pydantic v2 BaseModel classes with nested models, Optional fields, lists and snake_case aliases.

Run jq filters against JSON in your browser. Supports def functions, modules, reduce/foreach, streaming, regex, dates, slurp/null-input flags and more — no install, nothing uploaded.

Validate, pretty-print, compact, sort and convert JSON Lines (NDJSON) files to and from JSON arrays, with per-line error reporting.

Convert text between camelCase, snake_case, PascalCase, UPPER_CASE, kebab-case, and more.

Count words, characters, sentences, paragraphs, and reading time.

Generate URL-friendly slugs from any text string.

Write Markdown and preview the rendered HTML output in real-time.

Compare two text blocks side by side and highlight the differences.

Generate placeholder lorem ipsum text in paragraphs, words, or lists.

Test regular expressions with real-time match highlighting, flags, and capture groups.

Bulk find and replace text with support for regex and case sensitivity.

Sort lines alphabetically, numerically, reverse or randomly.

Remove duplicate lines from text, keeping unique lines only.

Convert CSV, TSV, or pipe-delimited data into a formatted Markdown table.

Strip Markdown syntax and convert it to clean plain text.

Convert text to ASCII art using block character fonts.

Deep-inspect any string: byte length, entropy, character types, encoding, line endings.

Parse any URL into its components: protocol, host, path, query params, and hash.

Parse and edit URL query strings with key-value table view.

Parse User-Agent strings to detect browser, OS, device type, and engine.

Convert between units of length, weight, temperature, area, volume, speed, and more.

Press any key to see its keyCode, key name, code, and event properties.

Calculate Flesch Reading Ease and Flesch-Kincaid Grade Level for any text.

Extract and rank the most frequent keywords and phrases from any text.

Reverse text by character, word order, per-word letters, or line order.

Check if a phrase is a palindrome and find palindromic substrings within text.

Convert text to binary and binary back to text, with full UTF-8 support.

Generate cursed glitch text using combining Unicode diacritical marks, or remove it.

Check if two words are anagrams, or find anagrams of a word from a built-in word list.

Strip emoji characters from text and see a summary of what was removed.

Validate and convert between ISBN-10 and ISBN-13, with check-digit verification and hyphenated formatting.

Paste a regular expression and get a token-by-token, plain-English breakdown of what each part matches.

Count how often each word appears in a block of text, with stop-word filtering and a visual frequency ranking.

Convert plain text into leetspeak (1337 5p34k) with a configurable substitution intensity.

Convert English text to Pig Latin using standard consonant-cluster and vowel-start rules.

Summarize text using a transparent frequency-based sentence-scoring algorithm — no AI, just statistics you can inspect.

Analyze single-word, 2-word, and 3-word phrase frequency in a block of text — the classic on-page SEO keyword density check.

Convert any number into its full English word form (including currency and decimals), or convert word forms back into numbers.

Search and browse emoji by name or keyword, click to copy — with a recently-used list saved in your browser.

Paste markdown with headings and generate a GitHub-style table of contents with anchor links, in bulleted or numbered format.

Count characters, bytes, and lines in your text, with live progress bars against common platform limits like Twitter/X, SMS, and meta description length.

Count syllables per word and in total for any English text, using a vowel-group heuristic algorithm, with a per-word breakdown.

Convert text to proper title case following real style-guide rules (AP or Chicago), correctly lowercasing articles, conjunctions, and short prepositions unless they start or end the title.

Scramble the letters within each word of your text for word puzzles, anagram games, or "can you still read this?" demonstrations, with an option to keep first/last letters fixed.

Convert any text into the NATO/ICAO phonetic alphabet (Alpha, Bravo, Charlie...) letter by letter, for radio communication, spelling out names over the phone, or reference.

Generate an acronym or initialism from any phrase, with options to skip minor words (a, the, of...), choose a separator, and control letter casing.

Count vowels, consonants, digits, and other characters in any text, with a per-vowel breakdown and a top-10 consonant frequency chart.

Convert text to Grade 1 (uncontracted) Unicode Braille and back, with automatic number-sign and capital-sign handling.

Compute the Levenshtein edit distance and similarity percentage between two strings, showing how many insertions, deletions, or substitutions separate them.

Compute the Soundex code and a simplified Metaphone code for one or more words — classic phonetic-matching algorithms that group similarly-sounding words together.

Paste any text and generate an instant word cloud on canvas, sized by word frequency with common stop words filtered out, downloadable as a PNG.

Estimate how long a piece of text takes to read silently or read aloud, based on configurable words-per-minute rates, with live word, character, sentence, and paragraph counts.

Scan text for consecutive repeated words like "the the" (a common typo), plus a separate list of every word that repeats anywhere in the text with its count.

Calculate the point value of a word using standard English-language Scrabble tile values, with optional double word score and triple word score multipliers.

Encode text or files to Base64 format for safe data transmission.

Decode Base64 encoded strings back to plain text or binary data.

Percent-encode and decode URLs and query string parameters.

Encode and decode HTML entities like &, <, >, and more.

Convert between hexadecimal, decimal, binary, and octal number systems.

Look up Unicode code points, search by character name, and convert between encodings.

Decode and inspect JWT tokens — header, payload, and signature — without verification.

Encode and decode data using Bitcoin Base58 and Base58Check encoding.

Convert numbers between binary, octal, decimal, hex, and any base from 2–36.

Convert files to Base64 data URLs and decode data URLs back to files.

Encode and decode data using RFC 4648 Base32 — used in TOTP secrets and DNSSEC.

Encode and decode data using Base62 — ideal for URL-safe short IDs.

Encode and decode data using Ascii85/Base85, as used in PDF and PostScript.

Convert text to Morse code and back using the international Morse alphabet.

Encode and decode text using the ROT13 and ROT47 substitution ciphers.

Convert internationalized domain names (IDN) to and from Punycode (ACE).

Encode and decode Quoted-Printable text as used in email MIME content.

Encode or decode many URLs at once, one per line.

Convert text to International Morse Code and back, with audible dot/dash playback right in your browser.

Encode and decode text using ASCII85, the compact binary-to-text encoding used in Adobe PostScript/PDF and Git binary patches — roughly 25% more space-efficient than Base64.

Generate MD5, SHA-1, SHA-256, SHA-512, and SHA-3 hashes from text or files.

Generate strong, random passwords with configurable length and character sets.

Generate RFC 4122 UUIDs (v1, v4, v5, v7) individually or in bulk.

Check the strength of a password using entropy analysis and common patterns.

Hash and verify passwords using the bcrypt algorithm securely in the browser.

Generate HMAC signatures using SHA-256, SHA-512, or MD5 with a secret key.

Generate cryptographically secure random strings, tokens, and API keys.

Generate Universally Unique Lexicographically Sortable Identifiers (ULIDs).

Generate HTTP Basic Authentication headers from username and password.

Generate RSA public/private key pairs (2048/4096-bit) in PEM format using Web Crypto API.

Encrypt and decrypt text using AES-256-GCM with PBKDF2 key derivation — all client-side.

Generate BIP39 mnemonic seed phrases (12–24 words) for cryptocurrency wallets.

Paste a PEM certificate and decode its subject, issuer, validity, and SANs.

Enter a Base32 secret to see the current and next TOTP code, refreshed live.

Build a Content-Security-Policy header visually with per-directive source toggles.

Generate Subresource Integrity (SRI) hashes for CDN-hosted JS/CSS files.

Interactive step-by-step diagram of the OAuth 2.0 Authorization Code + PKCE flow.

Validate a card number's Luhn checksum, detect its network (Visa, Mastercard, Amex, etc.), and generate fake test numbers for sandbox use.

Validate an International Bank Account Number against the ISO 13616 checksum and see its country, check digits, and BBAN breakdown.

Validate a 17-character Vehicle Identification Number's check digit and decode its region, model-year code, and serial segment.

Generate URL-safe unique IDs in nanoid or CUID2-style format, with configurable length and batch count.

Generate a deterministic, SHA-1-based UUID v5 from a namespace and name — the same input always produces the same UUID.

Encode or decode text with a Caesar cipher shift (including ROT13), with all 25 possible shifts shown for brute-forcing an unknown key.

Compute the MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hash of any file directly in your browser — nothing is uploaded.

Compute the standard CRC-32 (zlib/gzip/PNG/Ethernet) checksum of text or a file.

Generate a memorable, cryptographically random diceware-style passphrase from a curated word list, with an entropy estimate.

Convert between PEM-format public/private keys and JSON Web Key (JWK) format using the Web Crypto API, entirely client-side.

Paste raw HTTP response headers and get a checklist audit of common security headers like HSTS, CSP, and X-Frame-Options.

Encrypt or decrypt text with the classic Vigenère polyalphabetic cipher using a repeating keyword, with a letter-by-letter breakdown.

Encode or decode text with the Atbash cipher — a mirror-alphabet substitution (A↔Z, B↔Y...) that is its own inverse.

Encrypt text with a repeating-key XOR cipher and view the result as hex or Base64, with matching decryption back to plain text.

Generate a valid MongoDB ObjectId or decode an existing one to reveal its embedded creation timestamp, random value, and counter.

Decode Twitter/X or Discord-style Snowflake IDs into their embedded timestamp, worker/datacenter ID, process ID, and sequence number, with selectable epochs.

Build a Gravatar avatar image URL from an email address using a client-side MD5 hash, with configurable size, default image style, and content rating.

Encrypt and decrypt text with the classic Playfair digraph substitution cipher using a 5×5 key square built from your keyword, with the generated square shown.

Encrypt and decrypt text with the classic Rail Fence transposition cipher, writing letters in a zigzag across a configurable number of rails, with a visual diagram of the pattern.

Encrypt and decrypt text with the Affine cipher, a mathematical substitution cipher using the formula E(x) = (a·x + b) mod 26, with validation that key A is coprime with 26.

Encrypt and decrypt text with the Hill cipher, a classic polygraphic substitution cipher that multiplies pairs of letters by a 2x2 key matrix modulo 26.

Encrypt and decrypt text with the Beaufort cipher, a reciprocal Vigenère variant using the formula C = (K − P) mod 26, so the same operation both encrypts and decrypts.

Encode and decode the Tap Code, which represents each letter as a pair of knock counts on a 5x5 grid — historically used by prisoners of war to communicate through walls.

Encrypt and decrypt text with the Polybius square, an ancient Greek coordinate cipher that maps each letter to a row/column pair on a 5x5 grid.

Encrypt and decrypt letter pairs with the Four-Square cipher, a digraph substitution cipher using four 5x5 grids and two independent keywords.

Encrypt and decrypt text with the Bifid cipher, a fractionating cipher that converts letters to Polybius coordinates, recombines rows and columns, and reads new letters back out.

Encrypt and decrypt text with the Trifid cipher, Félix Delastelle's three-dimensional extension of Bifid using a 27-letter cube of coordinates.

Encrypt and decrypt text with the Caesar Box (Scytale) cipher, a transposition cipher that writes a message into a rectangle and reads it back column by column.

Convert letters into a mix of 1-digit and 2-digit codes using a straddling checkerboard, the classic technique later used as the message-to-digits step of the Cold War-era VIC cipher.

Encode and decode text with Francis Bacon's 1605 steganographic cipher, where every letter becomes a unique 5-character A/B sequence.

Encrypt and decrypt text with the WWI German ADFGX field cipher, combining a keyed Polybius square with a columnar transposition.

Encrypt and decrypt text with the 19th-century Nihilist cipher, which converts letters to Polybius-square coordinates and adds a repeating keyword before producing a numeric ciphertext.

Validate EAN-8, EAN-13, and UPC-A barcode check digits using the standard weighted-modulo-10 checksum, or compute the correct check digit for a partial code.

Encode text into the classic Pigpen cipher, rendering each letter as its traditional grid symbol — a tic-tac-toe grid for A-R (dotted for J-R) and an X-grid for S-Z (dotted for W-Z).

Paste a hash string and see the likely algorithm(s) it could be, based on its length, character set, and format (hex, Base64, bcrypt, or Argon2).

Generate an RFC 9116 compliant security.txt file with contact, expiry, encryption, policy and canonical fields, with validation warnings.

Calculate SHA256 and legacy SHA1 fingerprints from an SSH public key to verify it matches what GitHub, servers or ssh-keygen -l report.

Decode WebAuthn clientDataJSON, authenticatorData and attestationObject, inspect flags and credential public keys, or create a test passkey to see real values.

Verify a JWT signature in your browser with a secret, PEM public key, JWK or JWKS. Supports HS, RS, PS and ES algorithms through WebCrypto.

Inspect an ASCII-armored PGP public key: user IDs, algorithm, key size or curve, key ID and fingerprint — parsed locally in your browser.

Benchmark PBKDF2 iteration counts on your own device to pick a work factor, with OWASP guidance for PBKDF2, bcrypt, scrypt and Argon2id.

Decode and verify a DPoP proof (RFC 9449): header, htm/htu/iat/jti claims, ath hash and JWK thumbprint, with signature verification.

Check npm or PyPI package names against popular packages for typosquatting and dependency-confusion risk.

Identify ML-KEM, ML-DSA and SLH-DSA public keys by OID, check sizes against FIPS 203/204/205 and flag quantum-vulnerable keys.

Generate PublicKeyCredentialCreationOptions and RequestOptions for passkeys with secure defaults and a random challenge.

Generate a PKCE code verifier, S256 code challenge and a complete OAuth 2.0 / OIDC authorization URL.

Format and beautify CSS code with consistent indentation and spacing.

Minify CSS by removing comments, whitespace, and redundant rules.

Visually build CSS box shadows with live preview and code output.

Visually design CSS border-radius shapes with a live preview.

Build CSS flexbox layouts visually with live code output.

Create beautiful glassmorphism effects with backdrop-filter and live preview.

Calculate and compare CSS selector specificity to debug cascade and override issues.

Visually build CSS clip-path shapes with draggable points and live preview.

Visually build CSS filter effects — blur, brightness, contrast, and more — with live preview.

Visually build CSS transforms — translate, rotate, scale, skew — with live preview.

Generate soft-UI neumorphic box-shadow effects with live preview and code output.

Generate colorful multi-point mesh gradient backgrounds with live preview.

Generate pure CSS triangles using the border trick, with live preview.

Interactive reference for all CSS cursor types with live hover demo.

Optimize and minify SVG files by removing unnecessary attributes and whitespace.

Convert SVG code to CSS background-image data URI for inline use.

Generate organic random blob shapes as SVG with adjustable complexity and instant copy.

Build a modular type scale from a base size and ratio, with generated CSS custom properties.

Visually build CSS Grid layouts with track sizing, gaps, and grid-template-areas.

Convert raw CSS declarations into equivalent Tailwind CSS utility classes.

Convert between px, rem, em, pt, vw, vh, and % using a configurable root font size and viewport width.

Visually design a CSS cubic-bezier() easing curve by dragging control points, with live animation preview.

Calculate the missing width or height from a known dimension and aspect ratio, with common presets.

Generate CSS media query breakpoints for mobile-first or desktop-first responsive design.

Generate a modular typography scale (heading sizes) from a base font size and a musical/classical scale ratio, with CSS custom properties output.

Generate a CSS clamp() font-size that scales linearly between a minimum and maximum size across a viewport width range.

Paste CSS and extract every custom property declaration and var() usage, with a report of unused and undeclared variables.

Test a CSS selector against editable sample HTML and see every matching element highlighted, using the real browser selector engine.

Visually build single or multi-layer CSS text-shadow values with live preview, adjustable offset/blur/color per layer, and copyable CSS.

Pick from several pure-CSS loading spinner styles (ring, dots, pulse, bars), customize size/color/speed, and copy ready-to-use HTML + CSS — no images or JS libraries.

Build a modern, minimal CSS reset from toggleable rule groups — box-sizing, margin removal, responsive media defaults, form inheritance, accessible focus styles, and more.

Convert a CSS length between pixels, rem, and em given a configurable root and parent font size, plus batch-convert a list of px values to rem.

Generate a shimmering CSS skeleton-loader placeholder (avatar + text, card, or list layout) with copyable HTML and CSS.

Build BEM (Block__Element--Modifier) class names from a block, element, and modifier, with kebab-case normalization and an example HTML snippet.

Build CSS gradient-filled text using background-clip: text, with adjustable colors, angle, and font size, plus a live preview and copyable CSS.

Generate a fluid CSS clamp(min, preferred, max) expression from two viewport-width/size breakpoints, for responsive typography and spacing that scales smoothly.

Design a custom scrollbar with adjustable width, thumb color, track color, and corner radius, generating CSS for both WebKit/Blink and Firefox with a live preview.

Build a @container CSS query that responds to a parent container's own size rather than the viewport, with the required container-type setup included.

Generate CSS mask-image rules for gradient-based edge fades and vignette effects, with a live preview and cross-browser -webkit- prefix included.

Build a CSS conic-gradient() with adjustable color stops, starting angle, and center position — ideal for pie charts, color wheels, and circular progress rings.

Generate a CSS-only 3D flip card using perspective, transform-style, and backface-visibility, with adjustable flip trigger, axis, and duration.

Build an accessible, pure-CSS iOS/Android-style toggle switch from a real checkbox input, with customizable size, colors, and animation speed.

Design a button visually — colors, hover state, padding, border radius, shadow, and font size — then copy ready-to-use HTML and CSS.

Preview all 16 CSS mix-blend-mode and background-blend-mode values live on two color layers, and copy the exact CSS.

Visually build Flexbox layouts with flex-direction, wrap, justify-content, align-items, and gap controls, plus a live preview of adjustable item counts.

Experiment with anchor-name, position-anchor, position-area and position-try-fallbacks with a live preview and copy-ready CSS.

Build same-document view transitions with live preview: fade, slide, scale and wipe, with duration, easing and reduced-motion CSS.

Format and beautify HTML markup with proper indentation.

Minify HTML by removing whitespace, comments, and optional tags.

Write HTML and instantly preview the rendered output in a sandboxed frame.

Convert Markdown to clean HTML markup ready to embed.

Convert HTML markup to clean Markdown, including tables and lists.

Remove unsafe HTML tags and attributes while keeping safe markup.

Extract plain text from HTML, preserving structure and optionally converting links.

Validate HTML structure for common errors, missing attributes, and accessibility issues.

Work out how many KB of JavaScript, CSS, images and fonts fit in your page budget for a target load time on 3G, 4G or cable connections.

Validate sitemap.xml for well-formed XML, URL limits, absolute URLs, duplicates, lastmod dates, changefreq and priority values, right in your browser.

Format and beautify JavaScript code with proper indentation and structure.

Minify JavaScript code for production by removing whitespace and comments.

Interactive reference for JavaScript array methods — edit the input and callback and see live results.

Paste a package.json and visualize its dependencies grouped by type with version-range analysis.

Convert HTML markup into JSX-compatible syntax for React components.

Format and validate YAML configuration files.

Convert YAML to JSON format with one click.

Convert YAML configuration files to TOML format.

Convert an array of YAML records into CSV format.

Convert YAML documents to XML markup.

Format, validate, and minify TOML configuration files.

Convert TOML configuration files to JSON format.

Convert TOML configuration files to YAML format.

Convert classic INI configuration file syntax (sections, key=value pairs, comments) into structured JSON, with automatic type coercion for booleans and numbers.

View and explore CSV data in a formatted, searchable table.

Convert CSV files or data to JSON arrays.

Generate SQL INSERT statements from CSV data.

Convert CSV data into structured YAML.

Convert CSV data into a TOML array of tables.

Convert CSV data into XML markup.

Compare two CSV files cell-by-cell, detecting added/removed rows and exactly which column values changed, with optional row matching by an ID column.

Open a Parquet file in your browser and inspect its schema, row groups, codecs, per-column sizes and key-value metadata without uploading it.

Format, beautify, and minify XML documents with syntax validation.

Validate XML documents and get detailed error messages with line numbers.

Minify XML by removing whitespace and comments to reduce file size.

Convert XML documents to JSON format with attribute and namespace support.

Convert XML documents to YAML format.

Test XPath expressions against XML documents and see matching nodes.

Format and beautify SQL queries for readability.

Convert SQL INSERT statements into a JSON array of row objects.

Convert SQL INSERT statements into CSV data.

Upload a .db/.sqlite file, browse its tables, and run SQL queries entirely in your browser.

Convert CREATE TABLE SQL statements into Prisma schema models.

Visualize INNER, LEFT, RIGHT, FULL, and CROSS joins with a Venn diagram and real computed results from editable sample tables.

Minify SQL queries by stripping comments and collapsing whitespace, while carefully preserving the exact contents of string literals.

Convert between Unix timestamps and human-readable dates in any timezone.

Build and parse cron expressions with a visual editor and next-run preview.

Convert times between any two timezones with DST awareness.

Calculate the exact difference between two dates in days, months, years, and more.

Calculate exact age in years, months, and days from a date of birth, plus total days lived and days until your next birthday.

See the current time in multiple timezones at once, with a searchable list of every IANA timezone — updates live, no server call.

Find the ISO 8601 week number for any date, plus its ISO week year, day-of-year, and the exact Monday–Sunday range of that week.

Add or subtract a list of HH:MM:SS time durations — like video clip lengths or work time logs — and get the running total in HH:MM:SS, total seconds, and decimal hours.

Check whether any year is a leap year under the Gregorian calendar rule, with a plain-English explanation of why, plus a list of nearby leap years.

Count business days (Monday-Friday) between two dates, or add a number of business days to a starting date, excluding weekends and any custom holiday dates.

Complete reference for all HTTP status codes with descriptions and use cases.

Search and browse all MIME types and their associated file extensions.

Calculate IP ranges, subnet masks, and broadcast addresses from CIDR notation.

Validate IPv4 and IPv6 addresses and get detailed information.

Look up well-known TCP/UDP ports and their associated services.

View detailed browser, device, screen, and hardware information.

Calculate Unix file permissions with a visual toggle grid and symbolic/octal notation.

Generate CORS headers and config snippets for Express, Next.js, Vite, and Nginx.

Validate and reformat a MAC address between colon, hyphen, dot, and bare notation, decode its unicast/multicast and universal/local bits, or generate a random one.

Build SPF and DMARC DNS TXT record strings from simple form inputs, ready to paste into your DNS zone.

Expand shorthand IPv6 addresses with :: zero-compression to their full 8-group form, or compress a full address back to its shortest valid representation.

Convert a umask to default file and directory permissions (and back), with symbolic notation and common presets like 022, 027 and 077.

Generate QR codes for URLs, text, contact info, and more with custom sizes.

Generate HTML meta tags for SEO, Open Graph, and Twitter Cards.

Generate a robots.txt file for your website with custom rules.

Generate .gitignore files for any language, framework, or tool.

Generate realistic fake JSON data for API mocking and testing.

Generate realistic random user profiles using the randomuser.me API.

Build a PWA manifest.webmanifest file with icons, theme colors, and display mode.

Generate an XML sitemap from a list of URLs with priority, change frequency, and last modified dates.

Generate beautiful SVG wave shapes for website backgrounds and sections.

Generate SVG placeholder images with custom size, color, and text — no external service.

Compress JPEG, PNG, and WebP images client-side using the Canvas API.

Crop images with precise pixel controls and aspect ratio presets — no upload needed.

Generate Code 128, EAN-13, and Code 39 barcodes as SVG in the browser.

Scan QR codes using your device camera or upload an image.

Focus timer with 25-minute work sessions, short breaks, and long breaks.

Generate JSON-LD structured data markup for articles, products, FAQs, and more.

Paste code and generate a beautiful, shareable screenshot with syntax-aware coloring — a Carbon.sh alternative.

Paste multiple URLs or text values and generate a QR code for each one at once.

Generate common open-source license text (MIT, Apache 2.0, BSD 3-Clause, ISC, GPL-3.0, Unlicense) with your year and name filled in.

Generate fake JSON test records — names, emails, addresses, dates, and more — from a configurable field schema.

Build a standard vCard 3.0 contact file with a scannable QR code for instant import into any phone's contacts app.

Generate a scannable QR code that lets phones join a WiFi network automatically, using the standard WIFI: QR payload format.

Generate a structured README.md with badges, installation, usage, contributing, and license sections from your project details.

Preview how your page's Open Graph and Twitter Card tags render on Facebook, X/Twitter, LinkedIn, and Slack, with the raw meta tags to copy.

Preview how your title tag and meta description will render as a Google search result, with pixel-based truncation warnings.

Build a valid RSS 2.0 XML feed from channel details and a list of items, with copy and download — no CMS or backend required.

Build a valid .ics calendar file for a single event — title, date/time, location, and description — downloadable and importable into any calendar app.

Paste a robots.txt file and test whether a specific URL path is allowed or disallowed for a given crawler user-agent, following real precedence rules.

Paste HTML and your page URL to check canonical tag presence, validity, self-referencing status, and common SEO mistakes like duplicate or relative canonicals.

Build a set of <link rel="alternate" hreflang> tags for international/multilingual SEO from a list of language codes and URLs, with validation for common mistakes.

Build accessible breadcrumb navigation HTML and matching schema.org BreadcrumbList JSON-LD from a simple list of page names and URLs.

Generate random adjective+noun usernames with an optional number suffix, using cryptographically strong randomness — great for signups, test accounts, or anonymous handles.

Generate random baby name suggestions from curated lists of popular girl, boy, and unisex names, optionally filtered by starting letter.

Generate a printable word search puzzle from your own word list — words are placed in random directions across a customizable grid, with an optional solution overlay.

Generate a crossword puzzle grid with numbered across/down clues from your own word + clue list, with words automatically interlocked at shared letters.

Build campaign URLs with utm_source, utm_medium, utm_campaign, utm_term and utm_content parameters, correctly encoded and ready to share.

Convert GraphQL SDL into TypeScript interfaces, enums, unions, input types and field-argument types.

Build cURL commands visually — set method, headers, auth, body, and options with a live cURL output.

Make HTTP requests directly from your browser — set method, URL, headers, and body, then inspect the response.

Build and visualize raw HTTP requests — see exactly what your request looks like on the wire.

Create and sign JWT tokens — set header, payload, and secret to generate a valid token.

Edit and validate OpenAPI specs with a live path/method summary and prettify tool.

Visually build GraphQL types, queries, and mutations into valid SDL output.

Convert Protocol Buffer .proto message and enum definitions into TypeScript interfaces.

Build a Postman Collection v2.1 JSON export with requests, headers, and folders.

Compare two JSON API responses side by side and see exactly which fields changed.

Visually build an HTTP request — method, headers, body — and see the real response using your browser's fetch().

Paste a curl command and get equivalent JavaScript (fetch), Python (requests), and Node.js (https) code.

Generate realistic sample JSON payloads for GitHub, Stripe, Slack, and generic webhooks to test your receiver endpoint without waiting for a real event.

Essential Git commands with explanations, examples, and quick copy.

Complete reference for CSS properties with browser compatibility notes.

Quick reference for regular expression syntax, flags, and patterns.

Complete reference for HTTP request and response headers.

Modern JavaScript ES6+ syntax reference — destructuring, async/await, arrays, classes, and more.

TypeScript reference covering types, generics, utility types, and type guards.

Python 3 reference — comprehensions, decorators, error handling, and modern syntax.

Go language reference — structs, interfaces, goroutines, channels, and generics.

Rust reference — ownership, borrowing, traits, pattern matching, and iterators.

SQL reference — joins, window functions, CTEs, aggregates, and transactions.

Advanced Git reference — interactive rebase, reflog, bisect, worktrees, and submodules.

Quick reference for React hooks, components, props, context, and performance patterns.

App Router reference — routing, data fetching, server actions, middleware, and rendering.

Vue 3 reference — template syntax, Composition API, components, slots, and routing.

Utility class reference for layout, spacing, typography, colors, and responsive design.

Angular reference — components, data binding, directives, services, and RxJS basics.

Express reference — routing, middleware, request/response objects, and error handling.

Django reference — models, migrations, views, URLs, templates, forms, and the ORM.

Flexbox reference — container/item properties, alignment, and common layout patterns.

CSS Grid reference — template columns/rows, placement, alignment, and layout patterns.

Reference for CSS transitions, keyframe animations, timing functions, and common patterns.

HTML5 reference — semantic elements, forms, media, global attributes, and basic APIs.

SVG reference — shapes, path data commands, gradients, transforms, filters, and animation.

Accessibility reference — ARIA roles, states, properties, and common accessible patterns.

SEO reference — meta tags, Open Graph, Twitter Cards, structured data, and Core Web Vitals.

Java syntax, collections, streams, generics, records, and switch expressions at a glance.

C# syntax, LINQ, async/await, records, pattern matching, and nullable reference types.

PHP syntax, arrays, string functions, superglobals, OOP, and modern PHP features.

Ruby syntax, blocks/procs/lambdas, arrays/hashes, enumerable methods, and symbols.

Server blocks, location matching, reverse proxy, SSL config, rewrites, and common directives.

Common cmdlets, pipeline operators, variables, control flow, and comparison operators.

Vim/Neovim modes, movement, editing, visual mode, search/replace, registers, and macros.

VS Code keyboard shortcuts for editing, navigation, multi-cursor, search, and debugging.

Common commands for npm, Yarn, and pnpm side by side — install, scripts, workspaces, and more.

systemctl commands, journalctl usage, unit file anatomy, timers, and troubleshooting.

Time and space complexity reference for common data structures and algorithms.

Searchable reference table of all 128 ASCII codes with decimal, hex, octal, binary, and character views.

Searchable reference for npm and Node.js package manager commands, with flags and real examples.

Searchable reference for browser, text editing, window management, VS Code, and terminal keyboard shortcuts on Windows/Linux and Mac.

Searchable, filterable reference for Emmet HTML and CSS abbreviation syntax, with expandable examples showing the generated markup or CSS for each abbreviation.

Searchable reference of common DNS record types (A, AAAA, CNAME, MX, TXT, NS, SOA, PTR, SRV, CAA, and DNSSEC records) with their purpose and a real-world example.

Find out what day of the week any date falls on, plus its day-of-year number, leap year status, and approximate week number.

Find the approximate moon phase for any date using a standard astronomical approximation — new moon, quarters, gibbous, and full moon, with a visual phase indicator.

Find which of the 12 Western zodiac signs a birth date falls under, along with its date range and classical element (Fire, Earth, Air, or Water).

Convert a dog's age into approximate human-equivalent years using the American Veterinary Medical Association's guideline — more accurate than the old "multiply by 7" rule.

Convert shoe sizes between US, UK, EU, and centimeters for men's and women's sizing, using standard published conversion charts.

Reference dimensions for A-series (A0-A7), B-series (B0-B7), and US/ANSI paper sizes (Letter, Legal, Tabloid), shown in millimeters, centimeters, or inches.

Calculate aspect ratio, total megapixels, and pixels-per-inch (PPI) from a screen resolution and physical diagonal size, with common resolution name lookup.

Convert between common cooking volume units (teaspoons, tablespoons, cups, pints, quarts, gallons, mL, liters) or weight units (ounces, pounds, grams, kilograms).

Find your Chinese zodiac animal and element from your birth year, based on the traditional 12-year animal cycle and 10-year elemental cycle.

Convert your dog or cat's age into human-equivalent years using scientifically-informed non-linear formulas, not the oversimplified "×7" myth.

Estimate your ovulation day, fertile window, and next expected period from your last menstrual period date and average cycle length.

Calculate body surface area using the Mosteller and Du Bois formulas from height and weight — commonly used for medication dosing and burn assessment.

Search the periodic table by element name, symbol, or atomic number to instantly find atomic mass, category, and other key facts.

Calculate the minimum recommended copper wire gauge (AWG) for a circuit based on current, run length, voltage, and acceptable voltage drop.

Estimate a child's weight-for-age percentile (0-36 months) compared to WHO reference data, using sex, age in months, and current weight.

Look up the mathematically optimal blackjack action (hit, stand, double, or split) for any hard total, soft total, or pair against any dealer upcard.

Calculate the "feels like" wind chill temperature from air temperature and wind speed using the official U.S. National Weather Service formula.

Convert a finger circumference or ring inner diameter measurement (in mm) into US, UK/AU, and EU ring sizes using a standard sizing reference table.

Complete reference for Docker CLI commands — containers, images, volumes, networks, and Compose.

Searchable reference for essential Linux/Unix commands with examples, flags, and descriptions.

kubectl reference — resources, deployments, rollouts, debugging, and troubleshooting.

Terraform/OpenTofu reference — CLI commands, resource blocks, variables, and state management.

Bash scripting reference — variables, arrays, loops, functions, and redirection.

Build a Dockerfile visually with base image presets, COPY/RUN/ENV rows, and multi-stage builds.

Build a docker-compose.yml with multiple services, ports, volumes, and dependencies.

Generate an Nginx server block for static sites or reverse proxies.

Build .env and .env.example files from common presets or custom key-value pairs.

Build a Makefile with targets, prerequisites, and commands using correct tab indentation.

Generate an .editorconfig file with root settings and per-file-type overrides.

Build a .prettierrc configuration with all common formatting options.

Build an .eslintrc.json configuration with environments, extends, and custom rules.

Paste nginx, Apache, or JSON logs to parse, filter, and aggregate them client-side.

Fill in a type, scope, and description to get a formatted Conventional Commit message.

Paste a git diff and generate a structured pull request description with a file summary and checklist.

Compare two semantic versions or check whether a version satisfies an npm-style range like ^1.2.0 or ~2.0.0.

Paste conventional-commit-style messages and generate a Keep a Changelog formatted release section, grouped by type.

Build a common Apache .htaccess file for HTTPS redirects, www handling, caching, gzip, security headers, and SPA routing.

Paste a package.json and see dependency counts, scripts, and flags for unpinned versions, deprecated packages, and missing fields.

Paste a Dockerfile and get static best-practice checks for unpinned base images, root user, apt cache bloat, and multi-stage build opportunities.

Generate an Apache/Nginx basic-auth .htpasswd line using real, verifiable apr1-MD5 or SHA-1 hashing — entirely client-side.

Generate a starter GitHub Actions CI workflow YAML for Node.js, Python, Go, Docker, or a static-site deploy.

Generate a tsconfig.json for Node.js (CommonJS/ESM), React/Vite, or library projects with real, recommended compiler option combinations.

Build a valid package.json from project metadata, npm scripts, and dependency lists — no syntax errors, no guessing field names.

Pick common editor, formatting, and workspace settings via checkboxes and generate a ready-to-use .vscode/settings.json.

Look up what a Bash/Linux process exit code means, plus browse a searchable reference table of common exit codes including 128+signal codes.

Turn a change type, optional ticket number, and short description into a clean, conventional, kebab-case git branch name plus a ready-to-run checkout command.

Test a glob pattern against a list of sample file paths to see exactly which ones match, supporting *, **, ?, character classes, and brace alternation.

Test a Cloudflare Pages _redirects file against any URL path: see which rule matches, the resulting destination and status code, with splat and placeholder support.

Generate a wrangler.jsonc for Cloudflare Workers with compatibility date, assets, routes, cron triggers and KV, D1, R2 and Workers AI bindings.

Convert Kubernetes resource quantities between millicores and cores, and between Mi, Gi, M, G and bytes for requests and limits.

Compare two .env files to find missing, extra and differing variables, with optional value masking so secrets stay hidden.

Test a Cloudflare Pages _headers file against any request path to see which headers are applied, with splat, placeholder and detach (!) support.

Convert a docker-compose.yml into Kubernetes Deployment, Service and PersistentVolumeClaim manifests, with warnings for settings that need manual review.

Convert a cron expression into GitHub Actions schedule, Cloudflare Workers cron trigger and Kubernetes CronJob config, and preview the next 10 run times.

Build a GitHub Actions strategy.matrix with axes, include and exclude entries, fail-fast and max-parallel, and preview the resulting job combinations.

Format and align Terraform .tfvars files, or convert between .tfvars and terraform.tfvars.json, entirely in your browser.

Build Cache-Control headers with max-age, s-maxage and stale-while-revalidate, get a Cloudflare _headers snippet, and estimate cache hit ratio and origin load.

Evaluate mathematical expressions safely — supports arithmetic, trig, logs, sqrt, and more.

Check if a number is prime, find primes up to N, prime factorization, and nearest prime finder.

Calculate percentages, percent change, and percent increase/decrease instantly.

Compute mean, median, mode, variance, standard deviation, and quartiles from a list of numbers.

A full scientific calculator with trig, logs, powers, and memory functions.

Generate random integers or decimals within a range, with optional uniqueness and precision controls.

Add, subtract, multiply, transpose, and invert matrices with determinant calculation.

Solve right triangles — find the missing side, area, perimeter, and angles.

Calculate Body Mass Index from height and weight, with metric and imperial units.

Add, subtract, multiply, and divide fractions, and simplify to lowest terms.

Convert between Arabic numbers (1-3999) and Roman numerals, with canonical-form validation in both directions.

Perform AND, OR, XOR, NOT, and shift operations on two numbers, with binary, hex, and decimal views.

Calculate your monthly mortgage or loan payment, total interest, and full amortization schedule — with optional extra monthly payments.

Perform arithmetic (add, subtract, multiply, divide) and bitwise operations (AND, OR, XOR, NOT, shifts) on binary numbers, with live decimal/hex cross-reference.

Convert a data size between bytes, KB/MB/GB/TB and their binary (KiB/MiB/GiB/TiB) equivalents, showing both the decimal (SI) and binary (IEC) systems side by side.

Project how an investment or savings balance grows over time with compound interest and optional regular monthly contributions, with a year-by-year breakdown.

Convert geographic coordinates between Decimal Degrees and Degrees-Minutes-Seconds (DMS) notation, in both directions.

Calculate the great-circle distance and initial compass bearing between two latitude/longitude points using the Haversine formula.

Calculate the exact probability of every possible sum when rolling any number of dice with any number of sides, using full combinatorial math rather than simulation.

Estimate your daily calorie needs using the Mifflin-St Jeor equation, based on your age, sex, height, weight, and activity level.

Convert between Celsius, Fahrenheit, and Kelvin instantly — edit any field and the other two update automatically.

Generate the Fibonacci sequence up to any number of terms with exact BigInt precision, plus the golden-ratio approximation of the last two terms.

Calculate the greatest common divisor and least common multiple of two or more integers, with a visible step-by-step Euclidean algorithm trace.

Solve ax² + bx + c = 0 using the quadratic formula, showing the discriminant, both roots (real or complex), and the parabola's vertex.

Calculate nPr (permutations) and nCr (combinations) for a given n and r, with exact BigInt precision and the formula shown step-by-step.

Calculate total hours worked from clock-in/clock-out times across multiple days, with an optional unpaid break deducted per day, plus a decimal-hours total for payroll.

Calculate a discounted price from an original price and percent off, with support for two sequential ("stacked") discounts and the effective combined discount rate.

Add sales tax to a pre-tax price, or reverse-calculate the pre-tax price and tax amount from a tax-inclusive total, given a tax rate.

Calculate the selling price and profit amount from a cost and markup percentage, where markup is expressed as a percentage of cost (distinct from profit margin, a percentage of selling price).

Calculate profit margin percentage from cost and selling price, or find the selling price needed to hit a target margin — margin is always a percentage of selling price, distinct from markup (a percentage of cost).

Calculate the break-even point — in units and revenue — from fixed costs, price per unit, and variable cost per unit, the point where total revenue equals total costs.

Calculate your grade point average by entering letter grades and credit hours for each course, on either a 4.0 or 5.0 grading scale.

Estimate how much fuel a trip will use and what it will cost, from trip distance, vehicle fuel efficiency (MPG, L/100km, or km/L), and fuel price.

Estimate body fat percentage using the U.S. Navy circumference method — neck, waist (and hip for women), and height measurements, no calipers or scan required.

Convert between bytes, KB/MB/GB/TB (decimal, 1000-based) or KiB/MiB/GiB/TiB (binary, 1024-based), showing all units side by side at once.

Calculate return on investment (ROI) and annualized return (CAGR) from an initial investment, final value, and holding period.

Project the future value of your retirement savings from current balance, monthly contributions, years until retirement, and an expected annual return, compounded monthly.

Enter a partially-filled 9x9 Sudoku grid and instantly solve it using a backtracking algorithm — or load a classic example puzzle.

Calculate the minimum hourly rate you need to charge based on your target take-home income, business expenses, estimated tax rate, and billable hours.

Estimate total fencing project cost from linear footage, price per foot (material + installation), and any gates.

Track a personalized list of assets and liabilities and calculate your total net worth.

Calculate the monthly contribution needed to reach a specific savings goal by a target date, accounting for current savings and interest earned.

Convert an hourly wage to an equivalent annual salary, or an annual salary back to an hourly rate, based on hours per week and working weeks per year.

Calculate regular pay, overtime pay, and total weekly pay from an hourly rate, overtime multiplier, and hours worked past a weekly threshold.

Compare the debt snowball (smallest balance first) and debt avalanche (highest interest rate first) payoff strategies across multiple debts, with total months and interest paid.

Scale a list of recipe ingredients up or down for a different number of servings, automatically recalculating each quantity including fractions and mixed numbers.

Estimate ideal body weight from height and sex using four classic medical formulas: Devine, Robinson, Miller, and Hamwi.

Calculate your waist-to-hip ratio and see the corresponding WHO health-risk category based on your sex.

Calculate your target heart rate training zones from age and resting heart rate using the Karvonen formula.

Calculate the cubic yards of concrete and number of 80 lb pre-mix bags needed for a slab from its length, width, and thickness.

Estimate how many gallons of paint and what total cost you'll need based on wall area, number of coats, and coverage per gallon.

Calculate how many boxes of flooring (tile, laminate, hardwood, or vinyl) you need from room dimensions, a waste/cut allowance, and coverage per box.

Estimate your one-repetition maximum (1RM) for a lift using the Epley and Brzycki formulas, plus a percentage-based training table for programming lighter sets.

Calculate your running pace and speed from distance and time, plus predicted finish times for 5K, 10K, half marathon, and marathon at that same pace.

Calculate how many cubic yards and bags of mulch you need for a garden bed based on area and desired depth.

Calculate your overall course grade from multiple weighted categories (homework, quizzes, exams) — add, remove, and adjust categories and scores freely.

Calculate cubic yards and tons of gravel needed for a driveway, path, or base layer from area, depth, and material density.

Estimate your VO2 max (aerobic fitness) from the Cooper 12-minute run test distance, with a fitness category rating.

Estimate your recommended daily water intake in ounces and liters from body weight and daily exercise minutes.

Calculate ideal bedtimes or wake-up times based on 90-minute sleep cycles, so you wake up at the end of a cycle instead of mid-cycle.

Estimate a pregnancy due date and trimester milestones from the first day of the last menstrual period, using Naegele's rule.

Calculate the number of risers, actual riser height, number of treads, and total run for a staircase from total rise and target riser height.

Calculate simple interest and total repayment amount from principal, annual interest rate, and time in years — using I = P × r × t.

Calculate daily calorie needs (TDEE) and macronutrient targets (protein, carbs, fat in grams) from body stats, activity level, and a chosen macro split.

Calculate the daily, monthly, and yearly running cost of any appliance from its wattage, daily usage hours, and your electricity rate.

Generate a multiplication table for any number up to 10, 12, or 20 — a simple study aid for learning times tables.

Calculate roof surface area, roofing squares, and shingle bundles needed from footprint dimensions and roof pitch, including a waste factor.

Estimate your vehicle's value loss over time using a compounding annual depreciation rate, with a full year-by-year value breakdown.

Compare two products by their true per-unit cost (price ÷ quantity) to find which is actually the better deal, regardless of package size.

Estimate drywall sheets, screws, and joint compound needed for a room from its dimensions and sheet size, including a waste allowance.

Calculate the daily, monthly, and yearly fuel cost of your commute from one-way distance, vehicle MPG, gas price, and commute days per week.

Estimate how many years it takes for solar panel electricity savings to pay back the system cost, accounting for rising electricity rates and maintenance.

Estimate your Texas Hold'em pre-flop win probability against 1-8 opponents using a 5,000-hand Monte Carlo simulation of your two hole cards.

Calculate your recommended daily protein intake in grams based on body weight and activity/training goal, from sedentary maintenance to muscle-building or cutting.

Estimate how many additional inches of insulation and how many bags you need to reach a target R-value, based on your attic area and current insulation level.

Estimate blood alcohol concentration from body weight, biological sex, standard drinks consumed, and hours elapsed, using the Widmark formula.

Get complete color info: HEX, RGB, HSL, HSV, CMYK, and color harmonies.

Pick colors and convert between HEX, RGB, HSL, HSV, and CMYK — with color harmonies and palette export.

Check WCAG 2.1 AA/AAA color contrast ratios for foreground and background pairs.

Generate beautiful color palettes from a base color — shades, tints, complements, and harmonies.

Create CSS linear, radial, and conic gradients visually with full CSS output and copy.

Generate a Tailwind color configuration block from a list of HEX or RGB colors.

Upload an image and preview how it looks under protanopia, deuteranopia, tritanopia, and achromatopsia.

Extract the dominant color palette from any uploaded image, with hex codes and percentage breakdown.

Find the nearest standard CSS named color for any hex value using Euclidean RGB distance, or search and browse all 148 named colors.

Resize images to exact dimensions or presets entirely in your browser, with format and quality control.

Convert images between PNG, JPEG, and WebP formats directly in your browser.

Generate a full favicon set (16x16 to 512x512) from any source image, with ready-to-use HTML tags.

Convert SVG markup or files to PNG images with custom output size.

Convert raw SVG markup into a ready-to-use React JSX component.

Paste a base64 string or data URL to preview, inspect, and download the decoded image.

Paste an SVG path "d" string and see it rendered live on a grid with its bounding box.

Upload multiple images and resize them all at once, right in your browser.

Read the EXIF metadata embedded in a JPEG photo — camera, exposure, timestamp, and GPS tags — entirely in your browser.

Combine multiple SVG icon files into a single <symbol>-based sprite sheet, with ready-to-use <use> usage snippets.

Build a complete <img srcset> and sizes attribute from a base image URL pattern and a list of target widths.

Build an actual 1200×630 Open Graph / Twitter Card share image — title, subtitle, site label, and a gradient background — rendered on an in-browser canvas and downloadable as a real PNG file.

Strip EXIF, GPS, and ICC metadata from a JPEG, PNG, or WebP image by redrawing it onto a canvas and re-exporting a clean copy, entirely in your browser.

Convert plain text into bold, italic, script, and other stylized Unicode text variants.

Convert font sizes between px, rem, em, pt, and percent, with a quick reference table.

Preview heading and body font combinations with curated pairing presets.

Build a CSS font-family fallback stack from presets or custom fonts.

Add options and randomly spin to pick a winner — great for quick decisions.

Randomly pick one or more names from a list, with exclusion and history tracking.

Count down to a target date/time or a set duration, with quick-add time buttons.

Track daily habits with a weekly grid, streak counts, and local browser storage.

A precise stopwatch with lap tracking, fastest/slowest lap highlighting.

Find overlapping working hours across teammates in different timezones.

Calculate monthly loan payments, total interest, and a full amortization schedule for any fixed-rate loan.

Calculate tip amount and split a bill evenly between any number of people, with common tip percentage presets.

Build a simple, printable invoice with company/client details, line items, and automatic subtotal/tax/total calculations.

Read any text aloud using your browser's built-in speech synthesis engine — no server, no API key, no usage limits.

Roll one or more dice of any common type (d4-d100) or a custom side count, using cryptographically strong randomness, with a running roll history and total.

Build a single-elimination tournament bracket from a list of entrant names, with automatic byes assigned to top seeds when the entrant count isn't a power of two.

Randomly assign gift-giving pairs for a group, guaranteeing nobody draws their own name, with optional exclusion pairs for couples or family members.

Split a list of names into a chosen number of randomly shuffled, evenly-sized teams — great for sports, classroom groups, or team-building activities.

Prioritize tasks using the classic Urgent/Important 2x2 matrix — sort items into Do First, Schedule, Delegate, and Delete quadrants, saved locally in your browser.

Watch the current time displayed as a live Binary-Coded Decimal (BCD) clock, with each digit of hours, minutes, and seconds shown as a column of binary dots.

A simple To Do / In Progress / Done task board saved in your browser, using dropdown-based column moves instead of drag-and-drop.

Set an alarm for a specific time of day and get an audible chime plus a browser notification when it rings, right from your browser tab.

Flip one or more virtual coins using cryptographically strong randomness, with a running heads/tails tally and streak-friendly multi-coin flips.

Ask a yes/no question and shake the classic Magic 8-Ball for one of its 20 traditional randomized answers — affirmative, non-committal, or negative.

Test your typing speed (words per minute) and accuracy against a randomized short passage, timed live as you type.

Test your visual reaction time — click as soon as the box turns green, with live tracking of your last, best, and average reaction time across attempts.

Enter two names for a fun, purely-for-entertainment compatibility percentage — a deterministic hash, not a real prediction.

Play tic-tac-toe against a computer opponent that plays perfectly using the minimax algorithm — the best you can achieve is a draw.

Classic word-guessing game — guess letters to reveal a hidden word before running out of attempts, playable entirely with mouse or keyboard.

Play Connect Four against a minimax-powered computer opponent with alpha-beta pruning — drop discs, connect four in a row, and try to outsmart the AI.

Classic card-matching memory game — flip two cards at a time to find all 8 matching pairs in as few moves as possible.

Play the classic naval strategy game against the computer — place your 5 ships on a 10×10 grid, then take turns firing until one fleet is sunk.

Play the classic Minesweeper puzzle game — reveal cells, avoid the 10 hidden mines, and use number clues to flag them all on a 9×9 grid.

Play checkers against the computer — jump diagonally to capture pieces, reach the far row to become a king, and try to capture the entire enemy army.

Create your own custom flashcard deck with front/back text, then study by flipping, shuffling, and navigating through your cards.

Play Reversi (Othello) against the computer — sandwich opponent discs between your own to flip them, and win by controlling the most discs when the board fills.

Estimate token counts for GPT, Claude, and Llama-style models as you type.

Estimate LLM API costs from input/output token counts across popular models.

Build reusable AI prompt templates with {{variable}} placeholders and instant preview.

Convert JSON to TOON, a compact token-oriented format that reduces token usage in LLM prompts.

Generate Model Context Protocol (MCP) server configuration for Claude Desktop, Claude Code, Cursor and VS Code from a command, arguments and environment variables.

Create an llms.txt file that points AI assistants and LLM crawlers to your most important pages, following the llmstxt.org markdown format.

Generate an AGENTS.md file with setup, build, test, code style and PR instructions so AI coding agents can work in your repository correctly.

Estimate whether your text fits in the context window of popular LLMs such as GPT, Claude, Gemini and Llama, with an approximate token count and percentage used.

Convert a function/tool definition between OpenAI function calling, Anthropic tool use and Gemini function declaration formats.

Calculate cosine similarity, dot product, Euclidean distance and vector magnitudes between two embedding vectors pasted as JSON or comma-separated numbers.

Preview how a document is split into chunks for retrieval-augmented generation, with adjustable chunk size, overlap and recursive or fixed-size strategies.

Compare two versions of an LLM prompt side by side with word-level highlighting and an approximate token-count change.

Compare LLM API costs for standard, batch, and prompt-cached workloads to see how much a batch discount and caching could save on your volume.

Paste embedding vectors and get the cosine similarity, dot product and Euclidean distance between every pair.

Generate a valid SKILL.md with YAML frontmatter for Claude Code, Copilot, Codex and other Agent Skills compatible agents.

Validate a SKILL.md file against the Agent Skills specification: frontmatter, name format, description length and body size.

Build a robots.txt that allows or blocks GPTBot, ClaudeBot, PerplexityBot, Google-Extended and other AI crawlers separately for training and search.

Build an Agent2Agent (A2A) Agent Card JSON for /.well-known/agent-card.json with skills, interfaces, capabilities and security.

Validate an A2A Agent Card against required fields, interface bindings, skills and capabilities for versions 1.0 and 0.3.

Check an llms.txt file for the required H1, blockquote summary, sections and link format, so AI tools can read your site.

Lint an MCP tool definition and validate sample arguments against its inputSchema before you ship your server.

Convert an OpenAPI 3 document (JSON or YAML) into MCP tool definitions with inputSchema, annotations and HTTP hints.

Decode TOON (Token-Oriented Object Notation) back into JSON, with strict array-length and table-row validation. Also converts JSON to TOON.

Paste a JSON payload and compare the estimated token count of pretty JSON, compact JSON and TOON to see how much a prompt would shrink.

Load a CycloneDX or SPDX JSON SBOM and see components, versions, licenses, suppliers and dependency counts in a readable summary.

Compare two SBOMs and see added, removed and version-changed components and license changes between releases.

Interactive checklist for EAA / EN 301 549 / WCAG 2.2 AA compliance with a readiness score and gap report.

Check whether dependency licenses (MIT, Apache-2.0, GPL, AGPL, MPL) are compatible with your project license.