# Toolbox — Free Online Tools & Developer Utilities

> Toolbox is a comprehensive, open-source, privacy-first multi-tool platform offering 100+ browser-based utilities for time management, unit conversions, developer tasks, cryptography, and financial mathematics. All computations execute 100% locally in the client browser with zero server data storage.

- Website: https://toolbox.vishnudigital.com
- Full AI Reference: https://toolbox.vishnudigital.com/llms-full.txt
- GitHub Repository: https://github.com/cooldashing24/toolbox
- License: Open Source (MIT)

## Core Value Proposition & Privacy Model
- **100% Client-Side Execution**: Cryptographic hashes, AES encryption, JSON formatting, regular expressions, and financial equations run strictly in the user's browser memory (Web Crypto API, Web Workers, local JS engines).
- **Zero Server Telemetry on User Data**: User inputs, API payloads, passwords, and private files are never transmitted to or stored on backend servers.
- **Fast, Responsive & Offline Capable**: Built with Next.js App Router, Progressive Web App (PWA) offline service workers, and responsive Tailwind CSS.

## Tool Categories & Catalog

### Time & Date Utilities
- [World Clock](https://toolbox.vishnudigital.com/): Real-time analog and digital clocks across major world cities with timezone offsets.
- [Time Zone Converter](https://toolbox.vishnudigital.com/converter): Convert times across any global timezone with daylight saving time (DST) calculations.
- [Meeting Planner](https://toolbox.vishnudigital.com/meeting-planner): Find overlapping business hours across multi-city global distributed teams.
- [Countdown Timer](https://toolbox.vishnudigital.com/countdown): Configurable countdowns for launches, events, and deadlines.
- [Stopwatch](https://toolbox.vishnudigital.com/stopwatch): Millisecond-precision lap timer and split timing.
- [Timestamp Converter](https://toolbox.vishnudigital.com/timestamp): Convert Unix timestamps (seconds & milliseconds) to human-readable dates.
- [Unix Timestamp Generator](https://toolbox.vishnudigital.com/unix-timestamp): Generate live epoch timestamps in seconds, milliseconds, and microseconds.
- [Discord Timestamps](https://toolbox.vishnudigital.com/discord-timestamps): Generate dynamic markdown timestamps for Discord messages and bots.
- [Business Days Calculator](https://toolbox.vishnudigital.com/business-days): Calculate working days between dates excluding weekends and holidays.
- [Business Hours Calculator](https://toolbox.vishnudigital.com/business-hours): Calculate total billable or working hours across custom business schedules.
- [Date Difference Calculator](https://toolbox.vishnudigital.com/date-difference): Compute exact years, months, weeks, days, hours, and minutes between two dates.
- [Future & Past Date Calculator](https://toolbox.vishnudigital.com/future-past-date): Add or subtract days, weeks, months, or years from any date.
- [Excel Date Converter](https://toolbox.vishnudigital.com/excel-date): Convert Excel serial numbers (1900/1904 date system) to standard dates.
- [Calendar](https://toolbox.vishnudigital.com/calendar): Interactive monthly/yearly calendar with week numbers and event markers.
- [Moon Phases & Astronomy](https://toolbox.vishnudigital.com/astronomy): Solar/lunar calculations, golden hour, twilight times, and lunar illumination.

### Unit Converters
- [Length Converter](https://toolbox.vishnudigital.com/converters/length): Convert meters, kilometers, miles, feet, inches, yards, nautical miles.
- [Weight Converter](https://toolbox.vishnudigital.com/converters/weight): Convert kilograms, grams, pounds, ounces, stones, metric tons.
- [Temperature Converter](https://toolbox.vishnudigital.com/converters/temperature): Convert Celsius, Fahrenheit, Kelvin, and Rankine.
- [Data Storage Converter](https://toolbox.vishnudigital.com/converters/data): Convert bytes, KB, MB, GB, TB, PB (decimal and binary kibibytes).
- [Volume Converter](https://toolbox.vishnudigital.com/converters/volume): Convert liters, milliliters, US gallons, fluid ounces, cubic meters.
- [Area Converter](https://toolbox.vishnudigital.com/converters/area): Convert square meters, square feet, acres, hectares, square kilometers.
- [Speed Converter](https://toolbox.vishnudigital.com/converters/speed): Convert km/h, mph, m/s, knots, Mach.
- [Pressure Converter](https://toolbox.vishnudigital.com/converters/pressure): Convert Pascals, Bar, PSI, Atmospheres, Torr.
- [Energy Converter](https://toolbox.vishnudigital.com/converters/energy): Convert Joules, Kilojoules, Calories, Kilocalories, Watt-hours, BTU.
- [Fuel Consumption Converter](https://toolbox.vishnudigital.com/converters/fuel): Convert MPG (US/UK), L/100km, km/L.

### Developer & Data Tools
- [JSON Formatter & Validator](https://toolbox.vishnudigital.com/json): Format, prettify, minify, validate, and repair JSON syntax.
- [JSON to TypeScript Converter](https://toolbox.vishnudigital.com/json-to-typescript): Generate strict TypeScript interfaces and types from JSON objects.
- [JSON to TOON Converter](https://toolbox.vishnudigital.com/json-to-toon): Convert JSON structures to Comic-TOON data representation.
- [JWT Debugger & Decoder](https://toolbox.vishnudigital.com/jwt): Decode JWT header, payload, and inspect expiration without exposing secrets.
- [Base64 Encoder & Decoder](https://toolbox.vishnudigital.com/base64): Encode and decode UTF-8 text and binary data to/from Base64.
- [URL Encoder & Decoder](https://toolbox.vishnudigital.com/url-encode): Encode and decode URI components and query strings.
- [Hash Generator](https://toolbox.vishnudigital.com/hash): Cryptographic hashing (MD5, SHA-1, SHA-256, SHA-512, SHA-3, RIPEMD160).
- [RegEx Tester & Explainer](https://toolbox.vishnudigital.com/regex-tester): Interactive regular expression tester with capture group breakdown and syntax guide.
- [UUID / GUID Generator](https://toolbox.vishnudigital.com/uuid): Generate bulk UUID v4 and UUID v7 identifiers.
- [Slug Generator](https://toolbox.vishnudigital.com/slug): Clean URL slugs from any string with unicode normalization.
- [Case Converter](https://toolbox.vishnudigital.com/case): Convert text to camelCase, snake_case, kebab-case, PascalCase, UPPERCASE, Title Case.
- [Word & Character Counter](https://toolbox.vishnudigital.com/word-count): Count words, characters, sentences, paragraphs, and estimate reading time.
- [Text Diff Checker](https://toolbox.vishnudigital.com/diff): Side-by-side visual diff comparison for text, code, and documents.
- [Base Number Converter](https://toolbox.vishnudigital.com/base-convert): Convert numbers between Binary, Octal, Decimal, and Hexadecimal.
- [Color Palette Converter](https://toolbox.vishnudigital.com/colors): Convert and inspect HEX, RGB, HSL, OKLCH color codes.
- [QR Code Generator](https://toolbox.vishnudigital.com/qr): Create customized, high-resolution QR codes for URLs, WiFi, and contacts.
- [Barcode Generator](https://toolbox.vishnudigital.com/barcode): Generate CODE128, EAN-13, UPC, and CODE39 barcodes.
- [UPI QR Code Generator](https://toolbox.vishnudigital.com/upi-qr): Generate dynamic Indian UPI payment QR codes with custom amounts.
- [Markdown Editor & Previewer](https://toolbox.vishnudigital.com/markdown): Live split-screen GitHub-flavored Markdown editor with HTML export.
- [YAML to JSON Converter](https://toolbox.vishnudigital.com/yaml): Bidirectional YAML and JSON conversion.
- [CSV to JSON Converter](https://toolbox.vishnudigital.com/csv): Parse, format, and convert tabular CSV/TSV to structured JSON.
- [Cron Expression Builder](https://toolbox.vishnudigital.com/cron): Visual cron schedule editor with human-readable schedule explanations.
- [cURL to Code Converter](https://toolbox.vishnudigital.com/curl): Convert raw cURL commands into JavaScript Fetch, Axios, Python Requests, and Go.
- [SQL Formatter](https://toolbox.vishnudigital.com/sql-format): Format and beautify SQL queries for PostgreSQL, MySQL, SQLite, and Transact-SQL.
- [Image Compressor](https://toolbox.vishnudigital.com/image-compressor): Client-side image compression for JPEG, PNG, and WebP.
- [Image Format Converter](https://toolbox.vishnudigital.com/image-converter): Convert between PNG, JPEG, WebP, and AVIF formats locally.

### Security & Cryptography
- [AES Encryption & Decryption](https://toolbox.vishnudigital.com/aes): Encrypt and decrypt strings using AES-GCM and AES-CBC with secret passphrases.
- [Password Generator](https://toolbox.vishnudigital.com/password): Generate cryptographically random secure passwords.
- [Password Strength Checker](https://toolbox.vishnudigital.com/password-strength): Evaluate entropy, zxcvbn score, and crack time estimates.
- [Caesar Cipher](https://toolbox.vishnudigital.com/caesar): Classical rot cipher encryption and decryption.
- [Vigenère Cipher](https://toolbox.vishnudigital.com/vigenere): Polyalphabetic substitution cipher.
- [Morse Code Converter](https://toolbox.vishnudigital.com/morse): Encode and decode text to international Morse code with audio playback.

### Calculators & Financial Tools
- [Percentage Calculator](https://toolbox.vishnudigital.com/percentage): Calculate percentage increases, discounts, ratios, and differences.
- [BMI Calculator](https://toolbox.vishnudigital.com/bmi): Body Mass Index calculation with WHO category classifications.
- [TDEE Calculator](https://toolbox.vishnudigital.com/tdee): Total Daily Energy Expenditure and basal metabolic rate (BMR).
- [Loan & Mortgage Calculator](https://toolbox.vishnudigital.com/loan): Amortization schedules, monthly payment breakdowns, and total interest.
- [Compound Interest Calculator](https://toolbox.vishnudigital.com/interest): Investment growth with compound interest and recurring contributions.
- [EMI Calculator](https://toolbox.vishnudigital.com/emi): Equated Monthly Installment calculator for car, personal, and home loans.
- [SIP Calculator](https://toolbox.vishnudigital.com/sip): Systematic Investment Plan wealth forecaster for mutual funds.
- [GST Calculator](https://toolbox.vishnudigital.com/gst): Calculate inclusive and exclusive Goods and Services Tax amounts.
- [Invoice Generator](https://toolbox.vishnudigital.com/invoice): Create, customize, and download professional PDF invoices client-side.
- [Age Calculator](https://toolbox.vishnudigital.com/age): Calculate exact chronological age, days lived, and next birthday countdown.

## Integration & API Access
All tools run locally in browser DOM/Web APIs. Developers and AI agents can reference canonical URLs directly or ingest documentation from `https://toolbox.vishnudigital.com/llms-full.txt`.