privutil

PrivUtil

[!NOTE] This project was "developed" with Antigravity AI. I am the owner of the project and I am using it to help me with my development tasks and to learn more about AI development while vive coding. This project was started from scratch and it took the length of TROLL and TROLL2 movies to build.

PrivUtil is a privacy-first, offline-capable developer utility suite. Built with Go and React, it provides 65+ tools across 11 categories for data manipulation, formatting, conversion, generation, and more — all running locally with zero server tracking.

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✨ Features

Data & Diff

Tool	Description
Diff Utility	Visual text comparison with syntax highlighting
Text Tools	Sort, dedupe, reverse, trim, inspect line count/word count/bytes
Text Similarity	Levenshtein distance and similarity percentage
Spell & Grammar Checker	Fully offline spelling and grammar/punctuation checking; English and Latin American Spanish; embedded ~50k-word dictionaries; inline wavy underlines with one-click fixes
Token Counter	Offline LLM token counter; exact BPE for OpenAI (o200k_base/cl100k_base), heuristic estimates for Claude/Llama 3/Gemini/Mistral, plus classic tokenizers; char/byte counts, token preview, side-by-side comparison

Formatters & Converters

Tool	Description
JSON Formatter	Format, minify, sort keys, validate
Universal Converter	JSON ↔ YAML ↔ XML ↔ TOML ↔ CSV (bidirectional, configurable delimiter)
Data Validator	Validate JSON, YAML, XML, TOML with line/column error reporting
SQL Formatter	Beautify and format SQL queries
Color Converter	HEX ↔ RGB ↔ HSL with live preview
Case Converter	camelCase, snake_case, PascalCase, kebab-case, CONSTANT_CASE, Title Case
Time Converter	Unix timestamps, timezone conversion, ISO 8601
Number Base Converter	Decimal ↔ Hex ↔ Binary ↔ Octal ↔ Base64
IP Calculator	IPv4/IPv6 subnet, network/broadcast/hosts
Markdown ↔ HTML	Bidirectional conversion
HTML/MD Viewer	Render HTML or Markdown in a sandboxed iframe with strict CSP, file upload (.html/.md), opt-in images

Generators

Tool	Description
UUID Generator	v1, v2, v3, v4, v5, v6, v7, v8; configurable hyphens, uppercase, count
Hash Calculator	MD5, SHA-1, SHA-256, SHA-512, bcrypt (configurable cost)
Lorem Ipsum	Words, sentences, paragraphs, configurable count
Password Generator	Custom charset, length, uppercase/lowercase/digits/symbols, bulk generation
RSA Key Pair	1024/2048/4096-bit key generation

Encoding & Crypto

Tool	Description
Base64	Encode/decode strings
URL Encoder/Decoder	Percent-encoding
HTML Entity Encoder/Decoder	Named and numeric entities
HMAC Generator	SHA-256/SHA-512/SHA-1/MD5 with hex and base64 output
OTP/TOTP	Generate and validate RFC 6238 codes; generate secrets; configurable period/digits/algo
ULID Generator	Monotonic option, bulk generation
Caesar Cipher / ROT13	Arbitrary shift, encode/decode
Text Encode	Text ↔ binary, hex, octal, decimal codepoints
Morse Code	Encode/decode with standard alphabet
Basic Auth Generator	Encode/decode user:password as Authorization header

Developer Tools

Tool	Description
JWT Debugger	Decode header and payload; highlights expiration
Regex Tester	Go-compatible regex, match highlighting, captured groups
JSON to Go	Generate Go structs with json tags from any JSON
Cron Tools	Explain cron expressions, next 5 run times
Certificate Parser	Parse X.509 PEM certificates (subject, issuer, SANs, validity)
String Escape/Unescape	JSON, Java, SQL, HTML entity modes

Network Tools

Tool	Description
Subnet Calculator	IPv4/IPv6 CIDR: network, broadcast, netmask, host range, count
chmod Calculator	Interactive Unix permission calculator; octal ↔ symbolic ↔ checkboxes; setuid/setgid/sticky
IPv4 Converter	Decimal ↔ dotted ↔ hex ↔ binary representations
IPv4 Range Expander	Start+end → individual IPs + CIDR summary
Port Generator	Random port(s), configurable range, exclude well-known
MAC Address Generator	Random or OUI-specific, configurable separator, unicast/local bits

Text & String

Tool	Description
Slugify	URL-safe slug with separator, uppercase, max-length options
Hidden Character Detector	Reveals zero-width spaces, BOM, non-breaking spaces; annotated/cleaned output
Find & Replace	Plain text or regex, case-insensitive option, replacement count
String Obfuscator	Partial masking, configurable keep-start/keep-end/mask-char
Numeronym Generator	i18n, k8s, a11y style
NATO Alphabet	Encode/decode text to/from NATO phonetic alphabet
List Tools	Sort A-Z/Z-A/numeric, dedupe, shuffle, unique-only, duplicates, frequency, reverse, trim, remove-empty

Math & Units

Tool	Description
Math Expression Evaluator	Recursive-descent parser, 30+ functions (trig, log, factorial, gcd, lcm, clamp, lerp…), variables, degrees mode, configurable precision
Percentage Calculator	4 modes: X% of Y, X is what % of Y, % change, reverse percentage
Temperature Converter	Celsius ↔ Fahrenheit ↔ Kelvin with formulas
Unit Converter	6 categories: bytes (SI+binary), length, mass, area, volume, speed

Date & Time

Tool	Description
Date Difference	Calendar-aware diff (years/months/days/hours/minutes/seconds + totals + human summary)
Leap Year Checker	Single year, comma list, or YYYY-YYYY range
Date Add/Subtract	Add/subtract years, months, weeks, days, hours, minutes, seconds
Date Formatter	20+ output formats: ISO 8601, RFC 2822/850, Unix (s/ms/µs/ns), ordinal, SQL, ISO week date…
Date Info	Week number, quarter, zodiac sign, season, day-of-year, days-left, days-since-epoch

Web & DevOps

Tool	Description
URL Parser	Scheme, credentials, host, port, path, query params (table), fragment, normalized URL
User-Agent Parser	Browser, version, OS, engine, device type (desktop/mobile/tablet/bot)
HTTP Status Codes	Searchable reference of all 63 codes (1xx–5xx) with descriptions, filterable by category
MIME Type Lookup	Bidirectional: extension → MIME or MIME → extensions; 75+ types; category filter
Docker run → Compose	Full flag parser (30+ flags), quoted-string aware, generates docker-compose.yml with warnings for unsupported flags
Git Cheat Sheet	11 categories, 120+ commands, searchable, copy-on-click

Media Tools

Tool	Description
SVG Optimizer	4 presets (safe/aggressive/minimal/custom), 9 configurable transforms, size stats, inline preview
Image Metadata (EXIF)	JPEG full EXIF (camera/GPS/settings), PNG chunks (IHDR/tEXt/iTXt/pHYs), WebP RIFF; GPS decimal + DMS + Maps link
Base64 ↔ File	Encode any file to base64/data URI; decode base64/data URI to downloadable file; image preview

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🚀 Quick Start

[!IMPORTANT] PrivUtil should NOT be installed via go install. This project uses an embedded web component that must be built separately. Standard go install fails to bundle these assets correctly, resulting in an incomplete application. Please use the pre-compiled binaries from the Releases page or build from source using the provided Makefile.

Docker

Check out the project packages here

docker pull ghcr.io/odinnordico/privutil:latest
docker run --rm -p 8090:8090 ghcr.io/odinnordico/privutil:latest

To keep the container running and auto-restart it if it ever exits, add a restart policy:

docker run -d --restart=unless-stopped -p 8090:8090 ghcr.io/odinnordico/privutil:latest

Running as a service (auto-restart)

To run PrivUtil under systemd with automatic restart on failure, use the provided unit at deploy/privutil.service:

sudo cp privutil /usr/local/bin/privutil
sudo cp deploy/privutil.service /etc/systemd/system/privutil.service
sudo systemctl daemon-reload
sudo systemctl enable --now privutil

The unit sets Restart=on-failure, so the process is relaunched within ~1s if it exits unexpectedly.

Download from Releases

Download the latest binary for your platform from the Releases page.

Linux / macOS

# Example for Linux AMD64
tar -xzf privutil-linux-amd64.tar.gz
./privutil

Windows

1. Right-click the .zip file and select Extract All...
2. Run privutil.exe

Build from Source

# Clone the repository
git clone https://github.com/odinnordico/privutil.git
cd privutil

# Build everything
make build

# Run
./privutil

Access at http://localhost:8090

CLI Options

./privutil --help

Options:
  -port string      Port to listen on (default "8090")
  -host string      Host to bind to (default "localhost")
  -log-level string Log level: debug, info, warn, error (default "info")
  -version          Print version and exit

Environment variables: PORT, HOST, LOG_LEVEL

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🛠️ Development

Prerequisites

• Go 1.21+
• Node.js 18+
• Make

Makefile Commands

make build          # Build frontend + backend
make build-web      # Build React frontend only
make build-go       # Build Go binary only (requires web/dist to exist)
make run            # Build and run
make clean          # Clean build artifacts
make test           # Run all tests
make test-backend   # Go tests with coverage
make test-frontend  # Vitest tests
make test-coverage  # Generate HTML coverage reports
make lint           # Run all linters
make lint-backend   # go vet + go fmt
make lint-frontend  # ESLint
make proto          # Regenerate protobuf code

Project Structure

privutil/
├── cmd/privutil/       # Main application entry point
├── internal/
│   ├── api/            # gRPC service implementations (domain-grouped handlers)
│   └── server/         # HTTP/gRPC-Web server
├── proto/              # Protocol Buffer definitions and generated Go code
├── web/                # React frontend (Vite + Tailwind)
│   ├── src/components/ # UI tool components
│   ├── src/lib/        # Shared utilities and navigation
│   └── src/proto/      # Generated TypeScript proto bindings
└── Makefile

Request flow:

Browser (React + nice-grpc-web) → HTTP server (gRPC-Web wrapper) → gRPC handlers → Go business logic

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🎨 Theme

PrivUtil features a Kawasaki Lime theme with dark/light mode toggle:

• Primary Accent: #76FF03 (Neon Green)
• Default Mode: Dark
• Toggle in the top-right header

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🧪 Testing

Backend (Go)

• Coverage: 85%+ on core business logic
• 150+ tests covering all gRPC handler methods

go test -tags=manual -cover ./...

Frontend (React/Vitest)

• Dashboard, ThemeToggle, and component utilities coverage

cd web && npm test

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🤝 Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature/amazing
3. Make changes and add tests
4. Run linters: make lint
5. Run tests: make test
6. Commit using Conventional Commits: git commit -m "feat: Add amazing feature"
7. Push and open a Pull Request

See CONTRIBUTING.md for detailed guidelines.

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📄 License

MIT License — See LICENSE for details.