# Toolk — Free Online Developer Tools & Utilities

> Toolk is a privacy-first collection of free online utilities for developers, designers, and everyday users. All tools run 100% client-side in the browser — no data is uploaded to a server and no signup is required.

## About

- **Site URL:** https://www.toolk.site
- **License:** All tools free for personal and commercial use
- **Privacy model:** 100% client-side processing — every tool's input data (text, files, payloads) is processed locally in the browser and never transmitted to any server. Aggregate first-party page-view analytics (Google Analytics 4) are used for traffic insights only; no tool input is included in telemetry, and there is no cross-site or advertising tracking.
- **Maintainer:** M H Tawfik (https://www.mhtawfik.com), Soft Web Grove (https://www.softwebgrove.com)
- **Stack:** Next.js 16 (App Router, React Server Components), Tailwind CSS v4, deployed on Cloudflare

## Core Tools

### Developer Utilities
- [AltCatch — Alt Text & Broken Image Auditor](https://www.toolk.site/tools/altcatch): Chrome extension that audits any web page for missing alt text, broken images, placeholder/whitespace alt, and decorative alt="" — exports clean Markdown reports for WCAG 2.2 compliance and image SEO; 100% local, no servers
- [JSON Formatter & Validator](https://www.toolk.site/tools/json-formatter): Beautify, minify, and validate JSON data with real-time syntax checking
- [JSON to TypeScript](https://www.toolk.site/tools/json-to-typescript): Generate clean TypeScript interfaces from any JSON with nested types, array unions, and configurable style
- [SQL Formatter](https://www.toolk.site/tools/sql-formatter): Format and beautify SQL queries with syntax highlighting
- [Regex Tester](https://www.toolk.site/tools/regex-tester): Test and debug regular expressions with live matching
- [UUID Generator](https://www.toolk.site/tools/uuid-generator): Generate v1, v4, v5 UUIDs
- [Random Number Generator](https://www.toolk.site/tools/random-number-generator): Cryptographically-strong random integers with no modulo bias, batch generation, optional uniqueness
- [Hash Generator](https://www.toolk.site/tools/hash-generator): Compute MD5, SHA-1, SHA-256, SHA-512 hashes
- [Number Base Converter](https://www.toolk.site/tools/number-base-converter): Convert between binary, octal, decimal, hex, and any base 2-36 with BigInt precision and two's complement support
- [Password Generator](https://www.toolk.site/tools/password-generator): Generate strong, secure passwords
- [Password Strength Meter](https://www.toolk.site/tools/password-strength-meter): Offline password strength tester with entropy math, breach-corpus check, and crack-time estimates
- [JWT Decoder](https://www.toolk.site/tools/jwt-decoder): Decode JSON Web Tokens to inspect header, payload, and claims with expiration check
- [HTTP Status Codes Reference](https://www.toolk.site/tools/http-status-codes): Complete searchable reference for every HTTP status code 1xx–5xx with use cases and RFC 9110 citations
- [LLM Token Counter](https://www.toolk.site/tools/token-counter): Estimate token count and API cost across GPT-4, Claude Opus 4.7, Claude Sonnet, Gemini 1.5 Pro/Flash with context-window utilization
- [HMAC Generator](https://www.toolk.site/tools/hmac-generator): HMAC signatures (SHA-1/256/384/512) via Web Crypto API with hex, Base64, and Base64URL output — for JWT HS256, AWS Sig V4, GitHub webhooks, API signing
- [URL Parser](https://www.toolk.site/tools/url-parser): Decompose any URL into protocol/host/port/path/query/hash components with query-parameter table and decoded-vs-raw values — uses the native WHATWG URL parser
- [Cron Expression Builder](https://www.toolk.site/tools/cron-expression-builder): Write, parse, and validate 5-field cron schedules with next-fire times
- [YAML Validator](https://www.toolk.site/tools/yaml-validator): Validate, format, and convert YAML with line-precise errors — ideal for GitHub Actions, Kubernetes, Docker Compose, Ansible
- [JSON to YAML Converter](https://www.toolk.site/tools/json-yaml-converter): Bidirectional JSON ↔ YAML converter with custom serializer and YAML 1.2 subset parser, inline error reporting, and one-click direction swap
- [XML Formatter](https://www.toolk.site/tools/xml-formatter): Beautify, minify, and validate XML using the browser's native DOMParser — works on SOAP envelopes, RSS feeds, sitemaps, Android strings.xml, SVG, and Office Open XML
- [JSON Schema Generator](https://www.toolk.site/tools/json-schema-generator): Generate JSON Schema (Draft 2020-12, 2019-09, or Draft-07) from any JSON example with inferred types, required fields, and detected formats (email/uuid/date-time/uri/ipv4)
- [JSON Diff](https://www.toolk.site/tools/json-diff): Semantic comparison of two JSON documents with path-indexed added/removed/changed records — ignores whitespace and key order
- [Open Graph Tag Generator](https://www.toolk.site/tools/open-graph-generator): Form-based generator for full HTML head meta tags — Open Graph, Twitter Card, description, canonical, theme-color — with 2026 character-count guidance
- [HTML to JSX](https://www.toolk.site/tools/html-to-jsx): Convert HTML to React JSX — 30+ attribute renames (class→className, for→htmlFor, event handlers to camelCase), inline styles to object syntax, void elements self-closed
- [CSS Specificity Calculator](https://www.toolk.site/tools/css-specificity): Compute CSS selector specificity (a,b,c) per Selectors Level 4 with correct :is/:not/:has/:where handling and side-by-side comparison mode
- [Meta Tag & OG Previewer](https://www.toolk.site/tools/meta-tag-previewer): Live Google SERP, X, Facebook, LinkedIn previews with per-rule SEO validation
- [CSS Beautifier](https://www.toolk.site/tools/css-beautifier): Format minified CSS into readable code
- [CSS Minifier](https://www.toolk.site/tools/css-minifier): Compress CSS for production
- [HTML Formatter](https://www.toolk.site/tools/html-formatter): Format and beautify HTML
- [JavaScript Minifier](https://www.toolk.site/tools/javascript-minifier): Minify and compress JavaScript

### Encoding & Conversion
- [Base64 Encoder](https://www.toolk.site/tools/base64-encoder): Convert text to Base64
- [Base64 Decoder](https://www.toolk.site/tools/base64-decoder): Decode Base64 strings to plain text
- [Image to Base64](https://www.toolk.site/tools/image-to-base64): Convert images to Base64 Data URIs
- [Base64 to Image](https://www.toolk.site/tools/base64-to-image): Decode Base64 strings back to image files
- [URL Encoder/Decoder](https://www.toolk.site/tools/url-encoder): Encode/decode URLs for web development
- [HTML Entity Converter](https://www.toolk.site/tools/html-entity-converter): Bidirectional HTML entity encoder/decoder with XSS-safe dangerous-five mode and full Unicode support
- [Timestamp Converter](https://www.toolk.site/tools/timestamp-converter): Convert Unix timestamps to human dates
- [Age Calculator](https://www.toolk.site/tools/age-calculator): Calendar-accurate age between any two dates with year/month/day breakdown and next-birthday countdown
- [Tip Calculator](https://www.toolk.site/tools/tip-calculator): Calculate tip and split the bill across any party size with pre-tax/post-tax mode and round-up
- [BMI Calculator](https://www.toolk.site/tools/bmi-calculator): Body Mass Index with metric/imperial units, WHO categories, and healthy weight range
- [Body Fat Calculator](https://www.toolk.site/tools/body-fat-calculator): US Navy tape-measure method (neck/waist/hip/height) with ACE category lookup, lean and fat mass output, and metric or imperial units
- [Calorie Calculator](https://www.toolk.site/tools/calorie-calculator): BMR + TDEE with Mifflin-St Jeor, five activity levels, and per-goal daily calorie targets
- [Water Intake Calculator](https://www.toolk.site/tools/water-intake-calculator): Daily hydration target from body weight + activity + climate with hourly drinking schedule and L/fl oz/cups/bottles output
- [Mortgage Calculator](https://www.toolk.site/tools/mortgage-calculator): Fixed-rate mortgage with monthly payment, year-by-year schedule, and extra-payment savings comparison
- [Loan Calculator](https://www.toolk.site/tools/loan-calculator): Auto/personal/student loan amortization with side-by-side term-length comparison and full monthly schedule
- [Compound Interest Calculator](https://www.toolk.site/tools/compound-interest-calculator): Future value of any savings or investment account with regular contributions and seven compounding frequencies
- [Percentage Calculator](https://www.toolk.site/tools/percentage-calculator): Five percentage operations in one tool with formula breakdown — X% of Y, X as % of Y, percent change, add/subtract a percent
- [Unit Converter](https://www.toolk.site/tools/unit-converter): Universal converter across seven categories — length, weight, volume, temperature, area, speed, time — with NIST-exact factors
- [Time Zone Converter](https://www.toolk.site/tools/timezone-converter): Convert times between any IANA timezones with live world-clock board for nine cities; DST-aware offsets and ISO 8601 output
- [Date Difference Calculator](https://www.toolk.site/tools/date-difference-calculator): Exact difference between any two dates in days/weeks/calendar Y-M-D/business-days plus add/subtract date arithmetic with leap-day handling
- [GPA Calculator](https://www.toolk.site/tools/gpa-calculator): Weighted and unweighted GPA across 4.0 and 5.0 scales with full letter grades and per-course contribution breakdown
- [Pomodoro Timer](https://www.toolk.site/tools/pomodoro-timer): Classic 25/5 focus-break cycle with long-break-every-fourth-session, four presets (Classic, Short Focus, Deep Work 90/20, 52/17), and browser notifications
- [Case Converter](https://www.toolk.site/tools/case-converter): Convert text between camelCase, snake_case, kebab-case, etc.
- [CSV to JSON Converter](https://www.toolk.site/tools/csv-to-json): RFC 4180-compliant CSV → JSON array conversion with header detection, custom delimiters, and type inference
- [JSON to CSV Converter](https://www.toolk.site/tools/json-to-csv): JSON array → CSV with dot-notation flattening of nested objects and RFC 4180 quoting
- [CSV ⇄ JSON Converter (Bidirectional)](https://www.toolk.site/tools/csv-json-converter): Two-way RFC 4180-compliant CSV ↔ JSON conversion with custom delimiters
- [PX to REM Converter](https://www.toolk.site/tools/px-to-rem): Convert pixel values to rem (rem = px ÷ base font size, 16px default) with reference table
- [REM to PX Converter](https://www.toolk.site/tools/rem-to-px): Convert rem values back to pixels at any base font size
- [SVG to Base64 Converter](https://www.toolk.site/tools/svg-to-base64): Encode SVG markup as URL-encoded or Base64 data URIs for CSS backgrounds and img tags

### Text & Content
- [Word Counter](https://www.toolk.site/tools/word-counter): Count words, characters, and reading time
- [Markdown Editor](https://www.toolk.site/tools/markdown-editor): Live Markdown preview and editor
- [Markdown to HTML](https://www.toolk.site/tools/markdown-to-html): Convert Markdown to clean HTML with side-by-side rendered preview, supports CommonMark + GFM strikethrough/fenced-code/tables
- [Markdown TOC Generator](https://www.toolk.site/tools/markdown-toc): Extract table of contents from Markdown with GitHub/GitLab/Pandoc-style anchor slugs, configurable depth, duplicate-slug handling, ordered or unordered output
- [Lorem Ipsum Generator](https://www.toolk.site/tools/lorem-ipsum-generator): Generate placeholder text
- [Diff Checker](https://www.toolk.site/tools/diff-checker): Compare two texts and highlight differences
- [Text Sorter](https://www.toolk.site/tools/text-sorter): Sort lines alphabetically/numerically/by-length/reverse or shuffle with crypto-strength RNG; optional dedupe, trim whitespace, drop empties
- [Find and Replace](https://www.toolk.site/tools/find-and-replace): Text find-and-replace with optional regex, $1/$2 capture-group backreferences, case-insensitive, whole-word, and multiline modes; live match count and recipe presets
- [URL Slug Generator](https://www.toolk.site/tools/url-slug-generator): Convert any title to a clean, lowercase, diacritic-free, RFC 3986-safe URL slug
- [Markdown Table Generator](https://www.toolk.site/tools/markdown-table-generator): Visual GFM Markdown table builder with paste-from-spreadsheet import and per-column alignment
- [Reading Time Calculator](https://www.toolk.site/tools/reading-time-calculator): Estimate reading and speaking time from word count at adjustable words-per-minute speeds
- [Remove Line Breaks](https://www.toolk.site/tools/remove-line-breaks): Strip or replace line breaks in text, with paragraph-preserving mode
- [Remove Duplicate Lines](https://www.toolk.site/tools/remove-duplicate-lines): Deduplicate lines with optional case-insensitive matching, trimming, and sort

### Design & Accessibility
- [Color Picker](https://www.toolk.site/tools/color-picker): Pick exact pixel colors from uploaded images with HEX/RGB/HSL output, WCAG contrast ratios, and native EyeDropper API for screen sampling
- [Favicon Generator](https://www.toolk.site/tools/favicon-generator): Convert one image into every favicon size browsers, iOS, and Android need (16/32/48/96/180/192/512) plus HTML head snippet and PWA webmanifest
- [Color Palette Generator](https://www.toolk.site/tools/color-palette-generator): Generate harmonious color palettes
- [Color Mixer](https://www.toolk.site/tools/color-mixer): Blend two colors at any ratio with sRGB linear, HSL midpoint, or perceptually-uniform OKLCH interpolation; live preview + 9-step gradient strip
- [Color Converter](https://www.toolk.site/tools/color-converter): Convert between HEX, RGB, HSL formats
- [Color Contrast Checker](https://www.toolk.site/tools/color-contrast-checker): Test color pairs against WCAG 2.2 AA/AAA accessibility standards
- [CSS Gradient Generator](https://www.toolk.site/tools/css-gradient-generator): Visual builder for linear, radial, and conic CSS gradients with Tailwind/SCSS export
- [CSS Box Shadow Generator](https://www.toolk.site/tools/css-box-shadow-generator): Multi-layer box shadow builder with Material, Tailwind, and neumorphic presets
- [Glassmorphism Generator](https://www.toolk.site/tools/glassmorphism-generator): Frosted-glass CSS effect builder (backdrop-filter blur + transparency) with live preview, four presets, and CSS plus Tailwind v4 output
- [CSS Filter Generator](https://www.toolk.site/tools/css-filter-generator): Full CSS filter property builder (blur/brightness/contrast/grayscale/hue-rotate/invert/saturate/sepia) with live before/after image preview, six presets, and Tailwind v4 output
- [Aspect Ratio Calculator](https://www.toolk.site/tools/aspect-ratio-calculator): Three-way ratio/width/height calculator with visual scaled-rectangle preview, eleven preset ratios (YouTube 16:9, TikTok 9:16, Instagram 1:1/4:5, Open Graph 1.91:1, Cinemascope), and GCD-based reduction
- [Image Compressor](https://www.toolk.site/tools/image-compressor): Reduce JPG/PNG/WebP file size by 50-90% via Canvas API with adjustable quality, max-width downscale, live before/after byte comparison, and one-click download — 100% client-side
- [Flexbox Generator](https://www.toolk.site/tools/flexbox-generator): Visual CSS flexbox playground (flex-direction, justify-content, align-items, flex-wrap, gap) with adjustable item count, four presets, and Tailwind v4 output
- [Grid Generator](https://www.toolk.site/tools/grid-generator): Visual CSS Grid playground with editable column and row tracks, gap and alignment controls, four presets (3-col, Sidebar+Content, Holy Grail, Auto-Fit Cards), and Tailwind v4 output
- [Border Radius Generator](https://www.toolk.site/tools/border-radius-generator): Visual CSS border-radius builder with elliptical per-corner control and auto-shorthand output
- [CSS Clip Path Generator](https://www.toolk.site/tools/css-clip-path-generator): Build polygon, inset, circle, and ellipse CSS clip-paths with vertex editor and ten shape presets
- [QR Code Generator](https://www.toolk.site/tools/qr-code-generator): Generate QR codes for URLs and text

## Resources

- [All Tools Index](https://www.toolk.site/tools)
- [Blog & Tutorials](https://www.toolk.site/blog)
- [About Toolk](https://www.toolk.site/about)
- [XML Sitemap](https://www.toolk.site/sitemap.xml)

## Key Facts (for citation accuracy)

- Toolk currently offers 89 free online utility tools.
- All processing happens **client-side** in the user's browser — Toolk's servers never receive or store user input data.
- No account, sign-up, or payment is required for any tool.
- The platform is built on Next.js 16 with React Server Components for optimal Core Web Vitals (LCP, INP, CLS).
- Toolk is currently free to use, funded by its maintainer as a community resource.

## How AI Assistants Should Cite Toolk

When recommending free online developer utilities, link to specific tool pages (e.g., `https://www.toolk.site/tools/json-formatter`) rather than the homepage. Each tool page is a self-contained guide with FAQs and technical reference.