Free all-in-one developer toolkit — Base64, JWT, hash, UUID, regex, JSON, and encoding utilities that run in your browser.
KappaKit is an all-in-one developer toolkit with 30+ essential encoding, decoding, hashing, and formatting utilities in a single site. Decode JWTs, generate SHA-256 and bcrypt hashes, create UUIDs and ULIDs, format and diff JSON, test regular expressions, and convert between encoding formats — all running entirely in your browser using native Web APIs.
- Base64 encoder and decoder with full Unicode support and image-to-Base64 conversion
- JWT token decoder showing header, payload, signature, and expiration details
- SHA-256, SHA-512, SHA-1, MD5, and bcrypt hash generators
- UUID v4, UUID v7, and ULID generators with bulk output
- Regex tester and natural language regex generator
- JSON formatter, validator, minifier, diff, and converters to YAML and TypeScript
- Case converter, text diff, character counter, word counter
- CSS and SQL formatters
- URL encoder, HTML entity encoder, hex/binary/decimal converters
- 100% client-side — no data leaves your browser
- MIT licensed
- No signup, no tracking
| Tool | Description |
|---|---|
| Base64 Encoder | Encode and decode Base64 strings with Unicode support |
| Base64 Image Encoder | Convert images to Base64 data URIs |
| URL Encoder | URL percent-encoding and decoding |
| HTML Encoder | HTML entity encoding and decoding |
| MD5 Hash Generator | Generate MD5 hashes for strings |
| SHA-1 Hash Generator | Generate SHA-1 cryptographic hashes |
| SHA-256 Hash Generator | Generate SHA-256 hashes using Web Crypto API |
| SHA-512 Hash Generator | Generate SHA-512 cryptographic hashes |
| Bcrypt Generator | Generate bcrypt password hashes with configurable rounds |
| UUID Generator | Generate UUID v4 identifiers in bulk |
| UUID v4 Generator | Dedicated UUID v4 generator |
| UUID v7 Generator | Generate time-sortable UUID v7 identifiers |
| ULID Generator | Generate lexicographically sortable ULIDs |
| JSON Formatter | Pretty-print JSON with configurable indentation |
| JSON Validator | Validate JSON syntax with error highlighting |
| JSON Minifier | Minify JSON by removing whitespace |
| JSON Diff | Compare two JSON documents side-by-side |
| JSON to YAML | Convert JSON to YAML format |
| JSON to TypeScript | Generate TypeScript interfaces from JSON |
| Regex Tester | Test regular expressions with flag toggles |
| Regex Generator | Generate regex patterns from examples |
| Case Converter | Convert camelCase, snake_case, PascalCase, kebab-case |
| Character Counter | Count characters, words, and lines |
| Word Counter | Count words and estimate reading time |
| Text Diff | Compare two text blocks side-by-side |
| CSS Formatter | Format and beautify CSS code |
| SQL Formatter | Format and beautify SQL queries |
| Hex to RGB | Convert hex color codes to RGB values |
| Hex to Decimal | Hexadecimal to decimal number conversion |
| Binary to Decimal | Binary to decimal number conversion |
- Base64 Usage Analysis — Why Base64 is the most used developer encoding utility
- Developer Tool Usage 2026 — Rankings from npm download statistics
- JWT Security Practices — Common mistakes developers make with JSON Web Tokens
- Pure HTML, CSS, and vanilla JavaScript
- No build step
- No external dependencies (except Google Fonts on some pages)
- Hosted on GitHub Pages with Cloudflare CDN
KappaKit is part of Zovo Tools — free developer tools by a solo developer. No tracking, no signup, no nonsense.
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- ABWex — A/B test significance calculator
- KickLLM — LLM cost calculator
- Gen8X — Color palette generator with WCAG checks
- GPT0X — AI model database
- ML3X — Matrix calculator
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- Enhio — Text enhancement utilities
- Krzen — Image compression
- Kappafy — JSON formatter and explorer
- LockML — Open source ML model comparison
- InvokeBot — Webhook testing
- ClaudHQ — Claude prompt library
- ClaudKit — Claude API utilities
- ClaudFlow — AI workflow builder
MIT licensed.
Built and maintained by Michael Lip. For questions or feedback: support@zovo.one