Toolbox
Fast, private developer tools that run entirely in your browser. 141 tools, no sign up, no uploads.
- Open the page and start using it. There is no account, no sign up and no paywall.
- Everything runs as JavaScript in your own browser, so your input never reaches a server.
- Settings and saved work live in this browser and can be cleared at any time.
All tools
Crypto & Security
- Hash Text - MD5, SHA-1, SHA-256, SHA-512 digests
- HMAC - Keyed hash message authentication codes
- Encrypt / Decrypt - AES-GCM text encryption with a passphrase
- Token Generator - Strong random passwords and API tokens
- TOTP - Time based one-time passwords from a secret
- Basic Auth - Build Authorization headers from credentials
- Key Pair - Generate RSA and elliptic curve keys as PEM
- Password Strength - Entropy, weaknesses and time to crack
- Certificate Decoder - Read an X.509 certificate or signing request
- SSH Keys - Generate and inspect OpenSSH keys offline
Converters
- Base64 - Encode and decode text or files
- Color Converter - HEX, RGB, HSL, OKLCH and contrast checks
- Colour Palette - Tailwind style scales, a colour wheel and harmonies
- Case Converter - camelCase, snake_case, kebab-case and more
- Date & Time - Unix timestamps, ISO 8601 and relative time
- Number Base - Binary, octal, decimal, hex and any base
- JSON ⇄ YAML - Convert between JSON and YAML documents
- Text Encoder - Binary, hex, unicode, NATO, morse and ROT13
- List Converter - Sort, dedupe, wrap and rejoin lists
- Roman Numerals - Convert numbers to and from Roman numerals
- Currency - Convert between currencies with daily rates
- Morse Code - Translate text to Morse and play it back
- PDF Studio - Merge, split, rotate and convert PDFs
Web
- URL Encode - Percent-encode and decode URL components
- URL Parser - Break a URL into its parts and query params
- HTML Entities - Escape and unescape HTML entities
- JWT Parser - Decode and inspect JSON Web Tokens
- Keycode Info - Inspect keyboard events key by key
- Slugify - Turn any string into a clean URL slug
- HTTP Status - Searchable reference of HTTP status codes
- Header Review - Grade response headers for security and privacy
- Gradient Maker - Build CSS gradients with draggable colour stops
- CSS Animation - Keyframe presets with a cubic-bezier editor
Development
- Git Viewer - Open a git repository on your computer to see its commit graph, diffs and insights like hotspots and bus factor
- JSON Formatter - Format, validate, minify and explore JSON
- JSON Diff - Compare two JSON documents key by key
- SQL Formatter - Readable formatting for SQL statements
- XML Formatter - Indent and minify XML or HTML markup
- Crontab - Explain cron expressions and preview next runs
- Chmod - Unix permissions in octal and symbolic form
- Regex Tester - Test patterns with live matches and groups
- CSV Studio - Open, edit and convert CSV data in a table
- Mock Data - Generate realistic test data from a field list
- JSON Schema - Infer a schema from samples and validate documents
- API Spec Editor - Edit and check OpenAPI documents
- Docker Compose - Convert docker run commands to compose files
- Compose to K8s - Turn a compose file into Kubernetes manifests
- Kubernetes - Generate deployment, service and ingress manifests
- JSX to SVG - Convert React components to SVG and back
- GitIgnore Generator - Build a .gitignore from the tools you use
Network
- Subnet Calculator - IPv4 CIDR ranges, masks and host counts
- IP Converter - IPv4 in decimal, hex, binary and octal
- MAC Address - Generate and reformat MAC addresses
- DNS Lookup - Dig style record lookups over DNS-over-HTTPS
- Speed Test - Measure download, upload, latency and jitter
- Domain Lookup - RDAP records for a domain, IP or network
- WebSocket Tester - Connect to a socket and watch the frames
Text
- Lorem Ipsum - Placeholder copy in words, sentences or lists
- Text Stats - Counts, reading time and character analysis
- Text Diff - Compare two texts line by line
- Markdown - Write markdown and preview the HTML
- Emoji Picker - Browse, search and copy emoji with their code points
- Unicode Tables - Browse Unicode blocks and inspect any character
- Documents Studio - Write, format and export documents as PDF or Word, entirely in your browser
- Letters - Learn the Greek, Cyrillic, Japanese, Korean and Chinese letters
Math & Units
- Calculator - A calculator with basic, scientific, programmer and financial modes, history and keyboard support
- Math Evaluator - Evaluate expressions with functions and constants
- Unit Converter - Length, mass, data, temperature and time
- Journey Speed - Work out a trip's average speed and see how much time a faster pace really saves
- Function Plotter - Graph expressions with zoom, roots and derivatives
- Statistics - Summary, histogram and box plot for a set of numbers
Media
- QR Code - Generate scannable QR codes offline
- Image Converter - Convert, resize and compress images in the browser
- PNG Outline - Trace the outline of a picture into an SVG
- GIF Maker - Turn pictures or a video clip into an animated GIF
- Video & Audio - Transcode video and audio with WebAssembly
- Barcode - Code 128, EAN and Code 39 barcodes as SVG
- Icon Studio - Build an icon from thousands of parts, or describe one
- Favicon Maker - Every icon size, an .ico and the manifest
- Exif Metadata - Read and strip metadata from JPEG photos
- MP3 Metadata - Edit ID3 tags and artwork on MP3 files
- Placeholder SVG - Generate placeholder images as inline SVG
- ASCII Art - Text banners and image to ASCII conversion
- SVG Studio - View, clean, recolour and export SVG
- Gallery - Open a folder of photos to browse them by date, see their details and play a slideshow
- Music Player - Play music from a folder or files on your computer, with albums, artists, a queue and cover art
- Voice Recorder - Record audio and transcribe it on this device
- Mirror - Camera mirror with an adjustable ring light
- Screenshot Studio - Capture, annotate, blur and compare screenshots
- Paint - Pencil, shapes, fill and spray on a canvas
- Poster Studio - Design posters and social variants with an event QR
Science
- True Size of Countries - Drag countries across the map to compare their real size
- Periodic Table - All 118 elements with full properties
- Molecule Viewer - Vitamins, drugs and famous molecules in 3D
- Circuit Lab - Build and simulate basic electronic circuits
- Physics Lab - Balls, blocks, springs, rods, jacks and motors
- Logic Lab - Gates, flip-flops, counters, decoders and LED displays
- Optics Lab - Lenses, mirrors and prisms with real ray tracing
Local AI
- AI Builder - Describe a small web app and let a model in your browser write the files into a folder you choose
- AI Chat - Chat with a model running on this device
- AI Code - Explain, review, document and convert code
- AI Writer - Summarise, rewrite, translate and proofread
- Translate - Translate text with a model on this device
- AI Regex - Describe a pattern and get a tested regex
- MCP Tester - Connect to a Model Context Protocol server and try its tools, resources and prompts
- Inspector AI - Ask questions of your own documents, answered with references
Play
- Typing Test - Words per minute, accuracy and trouble keys
- Chess - Play the computer, learn the openings and train tactics
- Sudoku - Generated puzzles with notes and hints
- Blocks - Stack falling pieces and clear lines
- Memory - Flip cards and find the matching pairs
- Word Guess - Six tries to find the five letter word
- Drum Kit - Play pads and build a 16 step beat
- Tuner - Tune a guitar, bass or ukulele by ear or mic
- MIDI Keyboard - Playable synth with computer keyboard and MIDI input
- 2048 - Slide and merge tiles to reach 2048
- Minesweeper - Clear the grid without hitting a mine
- Snake - Eat, grow and do not bite yourself
- Breakout - Bounce the ball and clear every brick
- Pong - The original paddle duel against the machine
- Invaders - Hold the line against descending waves
- Solitaire - Klondike patience with draw one or three
- T-Rex Run - Jump the cacti in the offline runner
- Coin Flipper - Flip a coin and watch the odds even out
- Dice Roller - Roll any dice and see how the numbers fall
Utility
- UUID - Generate v4 and v7 identifiers in bulk
- Device Info - Everything the browser knows about this device
- Clock - World clocks, stopwatch and countdown timer
- Calendar - Month view with events saved per workspace
- Metro Maps - Animated metro maps with routes between stations
- Portfolio - Track holdings, allocation and profit or loss
- Notes - Quick scratch notes saved to this workspace
- Tasks - A lightweight checklist per workspace
- File Manager - Open a folder on your computer to browse, preview, edit and organise its files
- Time Zones - Line up cities and find the overlapping hours
- IBAN Validator - Check bank account numbers and read their parts
- Serial Console - Talk to a serial device over USB
- Bluetooth - Read, subscribe and write to GATT characteristics
- Gamepad Tester - Check every stick, trigger and button
- Code Scanner - Read QR codes and bar codes from the camera, a picture or the screen
- Tax Calculator - Work out net pay after tax in 23 countries, entirely on your device