Getting Started with SelfDevKit: The Complete Guide to 50+ Offline Developer Tools

Stop juggling browser tabs, worrying about data privacy, and waiting for slow online tools. SelfDevKit puts 50+ essential developer utilities in one fast, offline desktop app - here's how to get started.

Every developer knows the frustration: you need to decode a JWT, format some JSON, generate a UUID, and test a regex pattern. That's four browser tabs minimum, each from a different website with ads, tracking scripts, and the nagging question of whether your sensitive data is being logged somewhere. According to recent studies, developers waste an average of 2.5 hours per week struggling with poorly formatted JSON alone.

SelfDevKit eliminates this chaos entirely. One app, 50+ tools, zero internet required. Your data never leaves your machine, and every operation completes in milliseconds instead of waiting for network round trips.

This guide will take you from installation to productivity in minutes.

Installation
Quick tour: The interface
Essential tools walkthrough
All 27 tools by category
Keyboard shortcuts
Why offline matters
Next steps

Installation

Getting SelfDevKit running takes less than two minutes. Visit our download page to grab the installer for your platform.

macOS

Download the .dmg file for your Mac (Intel or Apple Silicon)
Open the downloaded .dmg file
Drag SelfDevKit into your Applications folder
Launch SelfDevKit from Applications or Spotlight

Windows

Download the EXE installer (recommended) or MSI installer
Run the installer and follow the prompts
Launch SelfDevKit from the Start menu or desktop shortcut

Which installer? The EXE installer is best for individual users with a simple graphical interface. The MSI installer is designed for IT administrators who need automated deployments and group policy management.

Linux

SelfDevKit supports all major Linux distributions with three package options:

AppImage (Recommended) - Works on any distribution. Just make it executable and run:
```
chmod +x SelfDevKit.AppImage
./SelfDevKit.AppImage
```
DEB Package - For Debian, Ubuntu, and derivatives
RPM Package - For Red Hat, Fedora, and derivatives

Quick tour: The interface

When you first open SelfDevKit, you'll see a clean, focused interface designed for speed:

Left sidebar: All tools organized by category. Click any tool to open it, or use Cmd+K to search.

Main area: The active tool with input/output panels. Most tools follow a consistent pattern - paste your data on the left, see results on the right.

Theme toggle: Switch between light and dark modes via the settings. Your preference persists across sessions.

Tool categories in the sidebar include:

Data Format - JSON, HTML, Markdown, SQL, and more
Security - JWT, passwords, secrets, encryption keys
Development - IDs, regex, text analysis, diffs
Network - URL parsing, DNS lookup
File - File generation, image conversion
Utility - Timestamps, colors, cron expressions

Everything loads instantly because nothing requires a network connection. The entire tool suite runs locally on your machine.

Essential tools walkthrough

Let's explore the tools you'll likely use most often with practical examples.

JSON Tools

The JSON Tools are probably what you'll reach for most frequently. Working with APIs means working with JSON constantly.

What it does:

Format minified JSON into readable, indented structure
Validate JSON and highlight syntax errors with line numbers
Search and filter large JSON documents
Switch between raw text and interactive tree view
Minify JSON for production use

Try it: Paste this minified JSON and hit Format:

{
  "user": {
    "name": "Jane",
    "roles": ["admin", "editor"],
    "settings": { "theme": "dark", "notifications": true }
  }
}

The dual-pane view shows your formatted JSON on one side and an expandable tree structure on the other. Click any node in the tree to highlight it in the raw view - incredibly useful for navigating complex API responses.

You can also convert JSON to TypeScript, Rust, Python, Go, or Ruby types using the JSON to Types tool.

JWT Tools

If you work with authentication, the JWT Tools become indispensable. No more copying tokens to random websites.

What it does:

Decode any JWT instantly to see header, payload, and signature
Verify signatures with your secret or public key
Check expiration status at a glance
Support for HS256, RS256, ES256, and other algorithms
Sign new tokens for testing

Try it: Paste any JWT from your application. You'll immediately see:

The decoded header (algorithm, token type)
The full payload with all claims
Whether the token is expired
Signature verification status (if you provide the secret)

This is especially valuable when debugging auth issues - no more wondering if the token is malformed or simply expired.

Base64 Tools

Encoding and decoding Base64 is a daily task for many developers. SelfDevKit provides dedicated tools for both text strings and images.

Base64 String Tools:

Encode any text to Base64
Decode Base64 back to readable text
Handle URL-safe Base64 variants
Copy results with one click

Base64 Image Tools:

Convert images to Base64 data URIs
Decode Base64 strings back to viewable images
Preview images before and after conversion
See image dimensions and file size

Perfect for embedding images in CSS, handling API payloads with binary data, or debugging encoded strings in logs.

ID Generator

The ID Generator supports every identifier format you'll encounter in modern development:

Supported formats:

UUID v4 - Random, universally unique identifiers
UUID v7 - Time-ordered UUIDs (great for database primary keys)
ULID - Lexicographically sortable unique identifiers
KSUID - K-Sortable Unique IDentifiers with embedded timestamps
Nano ID - Compact, URL-friendly unique strings
GUID - Microsoft-style identifiers

Generate single IDs or batch generate dozens at once. Each format includes a brief explanation of when to use it.

Need to analyze an existing ID? The ID Analyzer decodes UUIDs, ULIDs, KSUIDs, MongoDB ObjectIDs, and even Stripe IDs to show you the embedded timestamp and other metadata.

Regex Validator

Testing regular expressions in production code is painful. The Regex Validator provides a safe sandbox.

Features:

Real-time pattern matching as you type
Visual highlighting of all matches in your test string
Capture group extraction and display
Flag toggles (global, case-insensitive, multiline)
Built-in cheat sheet for common patterns

Paste your regex, paste your test data, and immediately see what matches. Adjust your pattern and watch the highlights update in real-time. No more console.log debugging loops.

Password Generator

Security matters. The Password Generator creates cryptographically secure passwords with full customization:

Options:

Adjustable length (8-128 characters)
Toggle uppercase, lowercase, numbers, symbols
Exclude ambiguous characters (0, O, l, 1)
Real-time strength analysis
Entropy calculation

Generate passwords for new accounts, API keys, or anywhere you need secure random strings. The strength indicator helps you balance security with usability requirements.

For more specialized secrets, check out the Secret Generator which creates API keys, JWT secrets, webhook secrets, encryption keys, and database passwords in various formats.

All 27 tools by category

Beyond the essentials above, SelfDevKit includes a comprehensive toolkit covering every common developer need.

Data Format & Conversion

JSON Tools - Format, validate, minify, and explore JSON with tree view
JSON to Types - Convert JSON to TypeScript, Rust, Python, Go, or Ruby types
HTML Tools - Format, minify, encode entities, validate, and preview HTML
HTML Viewer - Live HTML preview as you type
Markdown Editor - Edit with live preview and GitHub Flavored Markdown support
SQL Tools - Format and validate SQL queries with syntax highlighting
Base64 String Tools - Encode and decode text strings
Base64 Image Tools - Convert images to/from Base64 data URIs
Compression Tools - Compress and decompress with GZIP or Brotli

Security & Authentication

JWT Tools - Decode, verify, and sign JSON Web Tokens
Password Generator - Create secure passwords with strength analysis
Secret Generator - Generate API keys, JWT secrets, encryption keys
Key Pair Generator - Create RSA key pairs with customizable key size
Hash Generator - Generate MD5, SHA, BLAKE, CRC, and 15+ other hash algorithms

Development & Testing

ID Generator - Create UUID, ULID, KSUID, Nano ID, and more
ID Analyzer - Decode and inspect any ID format
Regex Validator - Test patterns with real-time matching
Text Inspector - Analyze text statistics, encoding, and formatting
Lorem Generator - Generate customizable placeholder text
Diff Viewer - Compare text and code side-by-side

Network & Web

URL Parser - Parse, inspect, and edit URL components
DNS Lookup - Query DNS records locally

File & Image

File Generator - Create test files of any type (PDF, Word, CSV, images)
Image Converter - Convert between PNG, JPG, WebP, GIF, TIFF, SVG
Image Operations - Crop, rotate, resize images in any format

Utility

Timestamps - Convert Unix timestamps, ISO 8601, and timezone conversions
Color Tools - Convert HEX, RGB, HSL, CMYK with contrast checker
Cronjob Generator - Build and understand cron expressions

Keyboard shortcuts

SelfDevKit is built for keyboard-driven workflows. Master these shortcuts to move even faster:

Shortcut (Mac / Windows & Linux)	Action
`Cmd+K` / `Ctrl+K`	Open quick search - find any tool instantly
`Cmd+1` through `Cmd+9` / `Ctrl+1-9`	Jump to tools 1-9 in sidebar
`Cmd+Enter` / `Ctrl+Enter`	Execute the primary action (format, encode, generate, etc.)
`Cmd+Shift+C` / `Ctrl+Shift+C`	Copy output to clipboard
`Cmd+V` / `Ctrl+V`	Paste from clipboard into input
`Cmd+Shift+V` / `Ctrl+Shift+V`	Paste and immediately process
`Cmd+L` / `Ctrl+L`	Clear all inputs and outputs
`Cmd+,` / `Ctrl+,`	Open settings

Pro tip: The quick search (Cmd+K on Mac, Ctrl+K on Windows/Linux) is your best friend. Type a few letters of any tool name and hit Enter. You'll never need to scroll the sidebar.

Why offline matters

SelfDevKit runs entirely on your machine. Here's why that matters:

Privacy: When you paste a JWT token, API key, or sensitive JSON into an online tool, you're trusting that website with your data. SelfDevKit processes everything locally - your secrets never touch a server.

Speed: Network latency adds up. Even a fast 50ms round trip becomes noticeable when you're making dozens of requests throughout the day. Local processing completes in single-digit milliseconds.

Reliability: No internet? No problem. Airplane WiFi acting up? Coffee shop network dropping? SelfDevKit works identically whether you're connected or not.

No tracking: We don't collect analytics on what you process, don't show ads, and don't sell your data. The app works the same way whether you're online or offline because there's simply nothing to phone home about.

For a deeper dive into the benefits of offline-first developer tools, read our post on why offline matters.

Next steps

You're now ready to boost your productivity with SelfDevKit. Here are some suggestions:

Explore the tools - Click through the sidebar and try each tool with sample data. Every tool has a "Sample" button to load example input.
Learn the shortcuts - Spend five minutes memorizing Cmd+K and Cmd+Enter. These two shortcuts alone will save you hours.
Replace your browser tabs - Next time you reach for an online JSON formatter or Base64 encoder, use SelfDevKit instead. The habit builds quickly.
Browse all features - See the complete list of tools with detailed descriptions on our features page.

Haven't downloaded yet? Get SelfDevKit now - it takes less than two minutes to install.

Have questions or feature requests? Reach out at support@selfdevkit.com. We read every email and use your feedback to prioritize new features.

Happy coding!