# DevHandy — Complete Technical LLM Documentation & Sitemap

> DevHandy (https://devhandy.io) is a client-side suite of 40+ web developer tools, utilities, formatters, validators, and generators.
> Architecture: 100% in-browser processing via Web APIs, Web Crypto, and Web Workers.
> Data Retention: Zero telemetry, zero external logging, zero backend storage of user payloads.

This file provides comprehensive technical reference for AI assistants, LLMs (ChatGPT, Claude, Cursor, Copilot, Perplexity), and automated indexing agents.

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## 1. System Architecture & Privacy Model

- **Client-Side Execution**: All data transformations (JSON parsing, code formatting, hashing, encryption, regex evaluation) run entirely in the user's browser sandbox using JavaScript/TypeScript standard APIs.
- **Web Crypto API**: Cryptographic operations (`SubtleCrypto` for SHA-256/SHA-512/SHA-384/SHA-1 and `crypto.getRandomValues` for UUIDs and Passwords) utilize native hardware-accelerated browser security primitives.
- **No Payload Transmissions**: User inputs (including proprietary source code, JWT tokens, and database dumps) are never transmitted to backend servers.
- **Performance**: Zero cold starts, instant response times, and full offline capability after initial service caching.

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## 2. Directory of Tools

### 2.1 JSON & Data Utilities

#### JSON Formatter
- URL: https://devhandy.io/tools/json-formatter
- Purpose: Format, beautify, and validate arbitrary JSON strings.
- Options: 2 spaces, 4 spaces, tab indentation; auto-repair trailing commas and unquoted keys.
- Output: Formatted JSON with syntax highlighting and 1-click copy.

#### JSON Validator
- URL: https://devhandy.io/tools/json-validator
- Purpose: Strict RFC 8259 syntax validation.
- Output: Pass/fail status, exact line and column numbers of syntax errors, and detailed error messages.

#### JSON Minifier
- URL: https://devhandy.io/tools/json-minifier
- Purpose: Strip unnecessary spaces, indentation, and newlines from JSON payloads.
- Output: Single-line compacted JSON for API bandwidth optimization.

#### JSON to TypeScript
- URL: https://devhandy.io/tools/json-to-typescript
- Purpose: Automatically generate typed TypeScript interfaces and type aliases from sample JSON payloads.
- Features: Handles deeply nested objects, arrays of primitives or objects, optional fields, and union types.

#### JSON to YAML
- URL: https://devhandy.io/tools/json-to-yaml
- Purpose: Convert JSON documents into standard YAML format for Docker, Kubernetes, and GitHub Actions configs.

#### YAML to JSON Converter
- URL: https://devhandy.io/tools/yaml-to-json
- Purpose: Parse YAML configurations and output clean, formatted JSON.

#### JSON to CSV Converter
- URL: https://devhandy.io/tools/json-to-csv
- Purpose: Transform array of JSON objects into downloadable RFC 4180 compliant CSV tables.

#### CSV to JSON Converter
- URL: https://devhandy.io/tools/csv-to-json
- Purpose: Parse tabular CSV or TSV data and convert into JSON array of objects or arrays.

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### 2.2 Web Development & Formatters

#### HTML Formatter
- URL: https://devhandy.io/tools/html-formatter
- Purpose: Indent, beautify, and clean messy HTML structures with proper tag nesting.

#### CSS Formatter
- URL: https://devhandy.io/tools/css-formatter
- Purpose: Beautify CSS stylesheets, format selectors, and align declaration blocks.

#### JavaScript Formatter
- URL: https://devhandy.io/tools/javascript-formatter
- Purpose: Beautify and standardize JavaScript/ECMAScript source code.

#### URL Encoder / Decoder
- URL: https://devhandy.io/tools/url-encoder-decoder
- Purpose: Bidirectional percent-encoding and decoding for query strings and URI components.

#### HTML Entity Encoder / Decoder
- URL: https://devhandy.io/tools/html-entity-encoder-decoder
- Purpose: Convert special characters into HTML entities or decode entities back to plain text.

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### 2.3 SEO & AI Crawlers

#### LLM Sitemap Generator
- URL: https://devhandy.io/tools/llm-sitemap-generator
- Purpose: Generate `llms.txt`, `llms-full.txt`, and AI search sitemaps following the llms.txt standard.
- Target Consumers: ChatGPT, Claude, Cursor, Copilot, Perplexity, and custom RAG pipelines.

#### XML Sitemap Generator
- URL: https://devhandy.io/tools/xml-sitemap-generator
- Purpose: Generate sitemaps.org compliant XML sitemaps with priority, changefreq, and lastmod tags.

#### Robots.txt Generator
- URL: https://devhandy.io/tools/robots-txt-generator
- Purpose: Create `robots.txt` configuration rules targeting Googlebot, Bingbot, and AI crawlers (GPTBot, ClaudeBot, PerplexityBot).

#### Meta Tag Generator
- URL: https://devhandy.io/tools/meta-tag-generator
- Purpose: Generate HTML `<meta>` tags, Open Graph properties, and Twitter Card declarations.

#### Open Graph Generator
- URL: https://devhandy.io/tools/open-graph-generator
- Purpose: Generate Open Graph tags (`og:title`, `og:description`, `og:image`, `og:url`, `og:type`) for social media link previews.

#### Twitter/X Card Generator
- URL: https://devhandy.io/tools/twitter-card-generator
- Purpose: Create `twitter:card`, `twitter:title`, `twitter:description`, and `twitter:image` tags.

#### Schema Markup Generator
- URL: https://devhandy.io/tools/schema-markup-generator
- Purpose: Generate Schema.org JSON-LD structured data schemas for Google Search rich snippets.

#### Schema Generator
- URL: https://devhandy.io/tools/schema-generator
- Purpose: General JSON-LD generator for WebSite, Organization, Product, and Service schemas.

#### FAQ Schema Generator
- URL: https://devhandy.io/tools/faq-schema-generator
- Purpose: Generate `FAQPage` structured data to produce rich FAQ accordion results in Google search results.

#### Breadcrumb Schema Generator
- URL: https://devhandy.io/tools/breadcrumb-schema-generator
- Purpose: Generate `BreadcrumbList` JSON-LD markup for navigational SERP breadcrumb trails.

#### Article Schema Generator
- URL: https://devhandy.io/tools/article-schema-generator
- Purpose: Generate `NewsArticle` and `BlogPosting` JSON-LD for rich cards and Top Stories.

#### Canonical Tag Generator
- URL: https://devhandy.io/tools/canonical-tag-generator
- Purpose: Generate `<link rel="canonical">` tags to prevent duplicate content penalties across parameterized URLs.

#### Hreflang Generator
- URL: https://devhandy.io/tools/hreflang-generator
- Purpose: Generate international and multilingual `<link rel="alternate" hreflang="...">` tag groups.

#### SERP Snippet Preview
- URL: https://devhandy.io/tools/serp-snippet-preview
- Purpose: Real-time visual simulator of desktop and mobile Google Search SERP snippets.

#### GA4 & GTM Data Layer Generator
- URL: https://devhandy.io/tools/ga4-gtm-datalayer-generator
- Purpose: Interactive Google Analytics 4 (GA4) and Google Tag Manager (GTM) dataLayer.push() code generator with multi-item e-commerce carts, tax/shipping calculations, Server-Side Meta CAPI event_id deduplication, GTM Preview simulator, and exports for React, Shopify Liquid, Vanilla JS, and GTM container JSON.

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### 2.4 Security & Cryptography

#### JWT Decoder
- URL: https://devhandy.io/tools/jwt-decoder
- Purpose: Inspect JSON Web Tokens (JWT) including Header (alg, typ), Payload claims (sub, exp, iat, aud), and signature validation info without transmitting private claims.

#### Base64 Encoder / Decoder
- URL: https://devhandy.io/tools/base64-encoder-decoder
- Purpose: Convert arbitrary text, UTF-8 strings, and files to and from RFC 4648 Base64 encoding.

#### Base64 Encoder
- URL: https://devhandy.io/tools/base64-encoder
- Purpose: Encode plain text into Base64 format.

#### Base64 Decoder
- URL: https://devhandy.io/tools/base64-decoder
- Purpose: Decode Base64 encoded strings back to plaintext.

#### Hash Generator
- URL: https://devhandy.io/tools/hash-generator
- Purpose: Compute cryptographic checksum hashes (SHA-256, SHA-512, SHA-384, SHA-1, MD5) using Web Crypto API.

#### UUID Generator
- URL: https://devhandy.io/tools/uuid-generator
- Purpose: Generate cryptographically random RFC 4122 version 4 UUIDs (GUIDs). Supports bulk generation.

#### Random String Generator
- URL: https://devhandy.io/tools/random-string-generator
- Purpose: Generate high-entropy random strings, API keys, tokens, and salting seeds.

#### Password Generator
- URL: https://devhandy.io/tools/password-generator
- Purpose: Generate high-entropy, customizable passwords with uppercase, lowercase, numbers, and special symbols.

#### SSL Certificate Checker
- URL: https://devhandy.io/tools/ssl-certificate-checker
- Purpose: Perform real-time TLS handshake audits to inspect domain SSL certificates, validity dates, CA chain trust, SANs, protocol & cipher support, and decode raw PEM/X.509 certificates.
- Features: Hostname verification, expiration countdown, certificate chain depth traversal, Subject Alternative Names search, and certificate download.

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### 2.5 Developer Utilities

#### Regex Tester
- URL: https://devhandy.io/tools/regex-tester
- Purpose: Test JavaScript regular expressions with real-time matching, group capture inspection, and syntax error alerts.

#### Cron Generator
- URL: https://devhandy.io/tools/cron-generator
- Purpose: Interactive builder for 5-part cron schedules with plain-English human translation and upcoming execution previews.

#### Unix Timestamp Converter
- URL: https://devhandy.io/tools/unix-timestamp-converter
- Purpose: Convert Unix epoch timestamps (seconds & milliseconds) to ISO-8601, UTC, and local date formats and vice-versa.

#### Color Converter
- URL: https://devhandy.io/tools/color-converter
- Purpose: Convert color values between HEX, RGB, HSL, and HSV with interactive visual color picker.

#### Text Case Converter
- URL: https://devhandy.io/tools/text-case-converter
- Purpose: Convert text between camelCase, snake_case, PascalCase, kebab-case, CONSTANT_CASE, Title Case, and Sentence case.

#### Text Diff Checker
- URL: https://devhandy.io/tools/text-diff-checker
- Purpose: Compare two texts or code files with visual inline and side-by-side added/removed character and line diffing.

#### Word Counter
- URL: https://devhandy.io/tools/word-counter
- Purpose: Real-time statistics on words, characters, sentences, paragraphs, reading time, and speaking time.

#### Character Counter
- URL: https://devhandy.io/tools/character-counter
- Purpose: Count characters with and without spaces, bytes, and custom character limits.

#### Lorem Ipsum Generator
- URL: https://devhandy.io/tools/lorem-ipsum-generator
- Purpose: Generate customizable placeholder dummy text by words, sentences, or paragraphs.

### 2.5 Design & UI Engineering

#### CSS Gradient Generator
- URL: https://devhandy.io/tools/css-gradient-generator
- Purpose: Interactive linear, radial, and conic gradient designer with customizable color stops, angle dials, and CSS code copy.

#### CSS Box Shadow Generator
- URL: https://devhandy.io/tools/css-box-shadow-generator
- Purpose: Multi-layer elevation and shadow generator with live preview, spread, blur, offset, and inset styling.

#### CSS Border Radius Generator
- URL: https://devhandy.io/tools/css-border-radius-generator
- Purpose: 8-point organic blob and rounded corner shaper with visual controls.

#### CSS Button Generator
- URL: https://devhandy.io/tools/css-button-generator
- Purpose: Design modern interactive buttons with hover lifts, active states, gradients, and cross-browser CSS.

#### Glassmorphism Generator
- URL: https://devhandy.io/tools/glassmorphism-generator
- Purpose: Modern frosted glass UI generator with backdrop-filter blur, opacity, reflection border, and CSS output.

#### CSS Clip-Path Generator
- URL: https://devhandy.io/tools/css-clip-path-generator
- Purpose: Interactive polygon, star, triangle, and chevron geometric clip-path designer with draggable anchor points.

#### CSS Text Shadow Generator
- URL: https://devhandy.io/tools/css-text-shadow-generator
- Purpose: Multi-layered text shadow designer for neon glow, 3D, and letterpress typography effects.

#### CSS Pattern Generator
- URL: https://devhandy.io/tools/css-pattern-generator
- Purpose: Pure CSS seamless background pattern generator including polka dots, grids, stripes, and checkerboards.

#### Flexbox Playground
- URL: https://devhandy.io/tools/flexbox-playground
- Purpose: Interactive visual sandbox for CSS Flexbox alignment, direction, wrapping, and child item sizing.

#### CSS Grid Generator
- URL: https://devhandy.io/tools/css-grid-generator
- Purpose: Visual 2D grid track, gap, and area layout builder with responsive template column controls.

#### CSS Clamp Calculator
- URL: https://devhandy.io/tools/css-clamp-calculator
- Purpose: Calculate mathematical clamp() formulas for fluid typography and responsive element scaling without media query bloat.

#### CSS Typography Scale Generator
- URL: https://devhandy.io/tools/css-typography-scale-generator
- Purpose: Generate harmonious modular typographic scales based on classic musical intervals.

#### CSS Units Converter
- URL: https://devhandy.io/tools/css-units-converter
- Purpose: Bidirectional converter between PX, REM, EM, VW, VH, and % with customizable root font size.

#### CSS Aspect Ratio Calculator
- URL: https://devhandy.io/tools/css-aspect-ratio-calculator
- Purpose: Calculate simplified aspect ratios and responsive padding-top formulas for media containers.

#### CSS Responsive Breakpoint Generator
- URL: https://devhandy.io/tools/css-responsive-breakpoint-generator
- Purpose: Preview responsive viewport breakpoints and generate mobile-first and desktop-first media queries.

#### CSS Animation Generator
- URL: https://devhandy.io/tools/css-animation-generator
- Purpose: Generate CSS keyframe animations for bounce, pulse, flip, spin, and wobble with interactive playback speed controls.

#### CSS Transform Generator
- URL: https://devhandy.io/tools/css-transform-generator
- Purpose: Visual 2D and 3D transform designer with perspective, rotate, scale, translate, and skew.

#### CSS Filter Generator
- URL: https://devhandy.io/tools/css-filter-generator
- Purpose: Image filter adjustment studio for blur, brightness, contrast, grayscale, hue, and sepia.

#### CSS Easing Generator
- URL: https://devhandy.io/tools/css-easing-generator
- Purpose: Interactive cubic-bezier curve designer with side-by-side animation race tracks.

#### CSS Loader Generator
- URL: https://devhandy.io/tools/css-loader-generator
- Purpose: Generate pure CSS loading spinners, pulsing dots, wave bars, and radar ripples.

#### Color Palette Generator
- URL: https://devhandy.io/tools/color-palette-generator
- Purpose: Generate harmonious color palettes based on triadic, complementary, and analogous rules with swatch exports.

#### Color Contrast Checker
- URL: https://devhandy.io/tools/color-contrast-checker
- Purpose: Check foreground/background color contrast ratios against WCAG 2.1 AA and AAA accessibility compliance standards.

#### CSS Specificity Calculator
- URL: https://devhandy.io/tools/css-specificity-calculator
- Purpose: Calculate and compare CSS selector specificity scores (IDs, classes, elements) to debug stylesheet cascade overrides.

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## 3. Machine-Readable Feeds & Endpoints

- Standard LLM Sitemap: https://devhandy.io/llms.txt
- Detailed LLM Reference: https://devhandy.io/llms-full.txt
- Well-Known LLM Sitemap: https://devhandy.io/.well-known/llms.txt
- Standard XML Sitemap: https://devhandy.io/sitemap.xml
- Robots Directive: https://devhandy.io/robots.txt