1. Why Use Online Developer Tools?
In the age of powerful CLI tools and IDE extensions, you might wonder why online tools still matter. Here's why developers keep coming back:
Instant Access
No installation, no configuration. Open a browser tab and you're ready. Perfect for quick checks.
Any Device
Works on your phone, tablet, or any computer. Debug that production issue from anywhere.
Visual Output
See formatted JSON with syntax highlighting, visualize regex matches, preview images. GUI beats CLI for quick visual inspection.
Easy Sharing
Copy formatted output, share tool links with team members. Great for collaboration.
🔒 Privacy-First Philosophy
SimpleDevTools processes everything in your browser using JavaScript. Your data never touches our servers. Verify this yourself: disconnect from the internet and the tools still work. Check network requests in DevTools - you'll see no data being sent.
2. Tools Overview
A quick reference of all available tools and their primary use cases:
| Tool | Primary Use | Common Scenarios |
|---|---|---|
| JSON Formatter | Pretty-print & validate JSON | API debugging, config files |
| JWT Decoder | Inspect JWT tokens | Auth debugging, token expiry |
| Base64 Encoder | Encode/decode Base64 | Data URIs, basic auth, emails |
| Regex Tester | Test regex patterns | Validation, parsing, search |
| UUID Generator | Generate UUIDs | Database IDs, unique keys |
| Hash Generator | Generate MD5/SHA hashes | File integrity, checksums |
| Password Analyzer | Check password strength | Security audit, entropy calc |
| Image Compressor | Compress images | Web optimization, uploads |
3. JSON Formatter & Validator
The most-used developer tool
Every developer works with JSON daily. Our formatter makes it readable, validates syntax, and spots errors instantly.
Key Features:
- Pretty-print minified JSON with proper indentation
- Syntax validation with clear error messages and line numbers
- Syntax highlighting for easy reading
- Minify to remove whitespace for production
- Tree view for exploring complex structures
When to Use:
- Debugging API responses that return minified JSON
- Validating configuration files before deployment
- Finding syntax errors in manually edited JSON
- Comparing JSON structures visually
4. JWT Decoder
Decode and inspect JWT tokens
Debugging authentication? See what's inside your tokens - header, payload, claims, expiration times.
Key Features:
- Decode all three parts - header, payload, signature
- Human-readable timestamps - see exp, iat, nbf as dates
- Algorithm detection - HS256, RS256, ES256, etc.
- Expiration status - instantly know if token is expired
- Color-coded display - each section clearly distinguished
When to Use:
- "Why is my API returning 401?" - Check if token is expired
- Verifying user claims and permissions in tokens
- Debugging OAuth/OIDC flows
- Checking token structure before implementation
5. Base64 Encoder/Decoder
Convert between binary and text-safe formats
Essential for embedding images, handling basic auth, and debugging encoded data.
Key Features:
- Text to Base64 - encode strings for safe transmission
- Base64 to Text - decode to see original content
- File support - encode/decode images and binary files
- URL-safe variant - for use in URLs without encoding issues
When to Use:
- Creating data URIs for embedding small images in HTML/CSS
- Setting up HTTP Basic Authentication headers
- Decoding email attachments (MIME)
- Debugging Base64-encoded API payloads
6. Regex Tester
Build and test regular expressions
Real-time matching with visual highlighting. See exactly what your pattern captures.
Key Features:
- Live matching - see matches as you type
- Capture groups - view grouped content separately
- All flags supported - global, case-insensitive, multiline, etc.
- Common patterns library - email, URL, phone templates
- Match highlighting - visual indication in test text
When to Use:
- Building input validation patterns
- Parsing log files or text data
- Search and replace in code editors
- Learning regex with immediate feedback
7. UUID Generator
Generate universally unique identifiers
Create UUIDs for database records, API resources, or any scenario needing unique IDs.
Key Features:
- Version 4 (random) - most commonly used
- Bulk generation - create multiple UUIDs at once
- Different formats - standard, uppercase, no hyphens
- Instant copy - one-click copy to clipboard
When to Use:
- Creating primary keys for database records
- Generating unique session or request IDs
- Tagging resources in distributed systems
- Creating file names that won't collide
8. Hash Generator
Generate cryptographic hashes
MD5, SHA-1, SHA-256, SHA-512 - compute checksums and verify file integrity.
Key Features:
- Multiple algorithms - MD5, SHA-1, SHA-256, SHA-512
- Text and file input - hash strings or uploaded files
- Instant computation - hashes calculated in real-time
- Compare hashes - verify against known checksums
When to Use:
- Verifying downloaded file integrity
- Creating checksums for data validation
- Generating cache keys based on content
- Comparing files for changes
9. Password Strength Analyzer
Analyze password security
Check entropy, detect patterns, estimate crack time. All analysis happens locally - we never see your password.
Key Features:
- Entropy calculation - mathematical measure of randomness
- Pattern detection - identifies common weaknesses
- Crack time estimation - how long would brute-force take
- Improvement suggestions - tips for stronger passwords
- 100% client-side - password never leaves your browser
When to Use:
- Testing passwords before using them
- Building password requirement UIs
- Security audits and training
- Understanding password entropy
10. Image Compressor
Compress images without losing quality
Reduce file sizes for faster web pages. All processing happens in your browser.
Key Features:
- Quality slider - balance size vs quality
- Multiple formats - JPEG, PNG, WebP support
- Batch processing - compress multiple images
- Size comparison - see before/after file sizes
- Preview - visual comparison before download
When to Use:
- Optimizing images for web performance
- Meeting file size limits for uploads
- Reducing storage costs
- Preparing images for email
11. Common Workflows
Here's how developers typically combine these tools:
🔍 Debugging API Authentication Issues
- Copy the JWT from your request headers
- JWT Decoder → Check if token is expired, inspect claims
- If payload looks Base64-encoded, use Base64 Decoder
- JSON Formatter → Pretty-print the API response to find error details
✅ Building Form Validation
- Regex Tester → Build and test validation patterns for email, phone, etc.
- Password Analyzer → Understand entropy requirements for password fields
- UUID Generator → Create unique form submission IDs
🚀 Optimizing Web Assets
- Image Compressor → Reduce image file sizes
- Base64 Encoder → Convert small icons to data URIs
- Hash Generator → Create cache-busting hashes for assets
🔐 Security Testing
- Password Analyzer → Test password requirements
- Hash Generator → Verify file integrity (checksums)
- JWT Decoder → Audit token contents for sensitive data
12. Frequently Asked Questions
Are these tools safe to use with sensitive data?
Why use online tools instead of CLI?
Can I use these tools offline?
Do you track user data or store inputs?
What's the best tool for debugging API responses?
How does the password analyzer work without sending data?
Are the hashes generated secure enough for production?
Can I suggest new tools or features?
Do the tools work on mobile devices?
How often are the tools updated?
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