The Developer Toolkit Problem
Web developers waste significant time:
•Hunting for a reliable JSON formatter that handles large payloads
•Finding a Base64 encoder that doesn't upload your credentials to a server
•Locating a JWT decoder that works offline without an account
•Testing regex patterns across multiple tools because none shows match groups clearly
ToolMasterApp consolidates 130+ developer and productivity tools in one place. All browser-based, all free, all private — your code and credentials never leave your device.
JSON Tools — Your Daily Driver
JSON Formatter — Format, validate, and minify JSON with syntax highlighting. Tree view for exploring deeply nested structures. Handles multi-MB API responses without freezing.
Key features:
•Real-time validation with exact error location
•Collapsible tree view for complex nested objects
•One-click minification for production
•Dark mode with colour-coded syntax
Use case: Paste a raw API response → instantly see the structure and find the field you need.
Encoding & Decoding Tools
Base64 Encoder/Decoder — Encode text, files, or images to Base64 and decode Base64 strings back to original content. Essential for:
•Authorization headers: Authorization: Basic base64(user:pass)
•Embedding images in CSS/HTML as data URIs
•Decoding Base64-encoded API responses
•Encoding binary file content for JSON payloads
URL Encoder/Decoder — Encode special characters for URLs and query strings. Decode percent-encoded URLs to human-readable format.
HTML Entity Encoder — Convert special characters to HTML entities for safe display in browsers.
Authentication & Security Tools
JWT Decoder — Paste any JSON Web Token to see:
•Header (algorithm, token type)
•Payload (claims, expiration, user ID)
•Signature verification status
Critical: Use a browser-based decoder. Pasting JWTs into external websites risks token theft. ToolMasterApp decodes locally — your tokens never leave your browser.
Password Generator — Generate cryptographically secure passwords with configurable length and character sets. Runs locally with the Web Crypto API — no network calls.
Hash Generator — Generate MD5, SHA-1, SHA-256, and SHA-512 hashes for text strings. Useful for verifying file integrity and debugging hash-based authentication.
Testing & Debugging Tools
Regex Tester — Test regular expressions with:
•Real-time match highlighting
•Named group extraction
•Global, multiline, and case-insensitive flag toggles
•Common regex pattern library (email, URL, phone, date)
API Tester — Send HTTP requests (GET, POST, PUT, DELETE) directly from your browser. Set custom headers, request body, and authentication. View response status, headers, and formatted body.
CORS Tester — Check CORS headers on any URL. Diagnose cross-origin request failures without writing code.
CSS & Design Tools for Front-End Developers
CSS Gradient Generator — Create linear and radial gradients with a visual editor. Copies the CSS code instantly.
Color Picker — Pick colors visually, convert between HEX, RGB, HSL, and CMYK. Generate color palettes from any base color.
Box Shadow Generator — Create CSS box shadows with live preview. Adjust blur, spread, offset, and color interactively.
Flexbox Playground — Test flexbox properties visually. Select justify-content, align-items, and flex-direction and see the result instantly.
Code Minifier — Minify CSS and JavaScript files. Reduces file size by 30–60% for production deployment.
Text & Document Utilities
Word Counter — Count words, characters, sentences, and paragraphs. Shows reading time estimate and keyword frequency.
Lorem Ipsum Generator — Generate placeholder text for mockups. Configurable word count, paragraph count, and format (plain text or HTML).
Case Converter — Convert text between camelCase, snake_case, kebab-case, PascalCase, and more — useful for renaming variables across codebases.
Diff Checker — Compare two text blocks side-by-side with highlighted differences. Useful for reviewing code changes without Git.
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