# Dev Tools !

> 70+ free, privacy-first developer tools that run entirely in your browser. No accounts, no data collection, offline-capable PWA. Built by Cosyslabs.

## What this site does

Dev Tools ! provides browser-based developer utilities across 8 categories. All tools run client-side — input never leaves your machine unless you explicitly use a backend-dependent feature (IP geolocation, webhook inbox). Tools are available via web UI, public REST API, npm CLI, MCP server, and browser/VS Code/JetBrains extensions.

## Tool Categories

### Encoders & Converters
- Base64 encode/decode (standard + URL-safe + data-URI)
- URL encode/decode (encodeURIComponent + encodeURI modes)
- HTML entity encode/decode
- Unicode escape/unescape (\uXXXX format)
- Hex ↔ ASCII / text ↔ hex
- JSON ↔ YAML converter
- Case converter (camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, Title Case)
- Base32 encode/decode (RFC 4648)

### Formatters & Validators
- JSON formatter/minifier/validator with syntax highlighting
- XML formatter/minifier/validator
- YAML formatter/validator
- Regex tester with match highlighting and replacement mode
- Diff viewer (line-by-line, side-by-side)

### Crypto & Security
- Hash generator: MD5, SHA-1, SHA-256, SHA-384, SHA-512
- HMAC generator: SHA-256, SHA-384, SHA-512
- JWT decoder (header + payload inspection, expiry check)
- Password generator (cryptographically secure, configurable complexity)

### Generators
- UUID generator: v4 (random) + v7 (time-ordered, RFC 9562)
- Lorem ipsum generator (words, sentences, paragraphs)
- URL slug generator (multiple separator and case options)
- Mock JSON generator from JSON Schema

### Date, Time & Math
- Unix timestamp converter (seconds/milliseconds ↔ ISO 8601 + local time)
- Cron expression builder and validator (5-field, with next-run preview)
- Date difference calculator (days, weeks, months, years)

### Text & String Tools
- Text counter (chars, words, sentences, paragraphs, reading time)
- Sort/deduplicate lines (asc/desc, trim, case-sensitive options)
- Find and replace (plain text + regex mode)

### Frontend & Design
- Color picker and format converter (HEX, RGB, HSL, HWB, OKLCH)
- WCAG contrast checker (2.1 AA + AAA for normal and large text)

### Network & Web
- HTTP status code reference (all 1xx-5xx codes with descriptions)
- IP geolocation lookup (public API, no key required)

## REST API

Base URL: `https://devtoolzy.com/devtoolzy/api/v1/`

- `GET /tools` — full tool catalog with slugs, names, descriptions, categories
- `GET /tools.json` — machine-readable catalog with JSON Schema for each tool
- `POST /tools/:slug/run` — run a tool server-side (top 20 tools; others return 501 browser-only hint)
- Rate limit: 60 requests/minute per IP, no authentication required for public endpoints
- CORS: open `*` — usable from any origin, browser or CLI

## MCP Server

Endpoint: `https://mcp.devtoolzy.com`
Discovery: `https://devtoolzy.com/.well-known/mcp.json`

Available MCP tools:
1. `base64_transform(text, mode)` — encode or decode Base64
2. `format_data(text, from, to)` — convert between JSON/YAML/XML/CSV/TOML
3. `hash_text(text, algorithm)` — compute MD5/SHA-1/SHA-256/SHA-512/HMAC
4. `decode_jwt(token)` — decode JWT header + payload (no verification)
5. `generate_id(type, count)` — generate UUID v4/v7, ULID, NanoID
6. `regex_test(pattern, flags, text)` — test regex with match details

## npm CLI

```bash
npx devtoolzy base64 encode "Hello, World!"
npx devtoolzy hash sha256 "hello"
npx devtoolzy jwt decode "eyJhbGc..."
npx devtoolzy uuid v4
npx devtoolzy format json < data.json
```

Install: `npm install -g @cosyslabs/devtoolzy`

## Content

- Blog: /blog — developer tutorials and explainers
- Topics: /topics — long-form pillar pages (e.g., "Complete Guide to Base64 Encoding")
- Glossary: /glossary — definitions of developer terms
- Cheatsheets: /cheatsheets — printable quick references (regex, HTTP status codes, cron syntax)
- Case studies: /case-studies — real-world usage examples

## Privacy

All tools run in your browser. No input data is transmitted to any server. Optional analytics (Google Analytics 4) only activates after explicit cookie consent, using Consent Mode v2 with no ad personalization. No user accounts required. No tracking by default.

## Contact

- Website: https://devtoolzy.com
- Email: support.cosyslabs@gmail.com
- Security: https://devtoolzy.com/.well-known/security.txt
- MCP docs: https://devtoolzy.com/mcp
- Trust dashboard: https://devtoolzy.com/trust

## Licensing

Tool logic (the run() functions): MIT License
Written content (blog, topics, glossary, case studies): CC-BY 4.0
Text corpus download: https://devtoolzy.com/corpus.zip (CC-BY 4.0, signed checksum)