URL Encoder & Decoder
Encode special characters to URL-safe format or decode percent-encoded URLs. Perfect for API development, query strings, and web applications.
Common URL Encoded Characters
%20%21%23%24%25%26%2B%2F%3A%3B%3D%3FIntroduction
Free Online URL Encoder & Decoder
The URL Encoder and Decoder lets you convert special characters to URL-safe format and decode percent-encoded URLs in seconds. Whether you're a developer building APIs, a web designer handling query strings, or a student learning about web standards, this tool helps you properly format URLs without installing software.
The tool works directly in your browser, making it fast, secure, and accessible from any device. No registration required, no data stored, and no limits on usage.
About the tool
What is URL Encoding?
URL encoding (also known as percent-encoding) is a mechanism for encoding information in a URL. It replaces unsafe ASCII characters with a "%" followed by two hexadecimal digits. For example, a space becomes %20, and an ampersand becomes %26.
This ensures URLs contain only characters that are safe for transmission over the internet. Our tool uses JavaScript's encodeURIComponent and decodeURIComponent functions, which properly handle UTF-8 characters and follow modern URL encoding standards.
Benefits
Why Use Our URL Encoder?
Saves Time
Encode and decode URLs instantly without writing JavaScript code or using browser console.
100% Secure
Your URLs never leave your browser. All encoding happens locally for maximum privacy.
Works Anywhere
Browser-based tool that works on any device - desktop, tablet, or mobile.
Offline Support
Once loaded, the tool works without internet connection for secure environments.
What you get
Key Features
Bidirectional Conversion
Encode text to URL-safe format or decode percent-encoded URLs.
UTF-8 Support
Properly handles international characters, emojis, and special symbols.
Character Reference
Built-in reference of common URL encoded characters.
Copy to Clipboard
One-click copy for encoded or decoded output.
Target users
Who Should Use This Tool?
Backend Developers
Build and test API endpoints with proper URL encoding
Frontend Developers
Handle URL parameters in web applications
Mobile Developers
Encode URLs for mobile app API calls
Security Engineers
Prevent injection attacks through proper encoding
DevOps Engineers
Debug URL issues in deployment and automation
Students
Learn about web standards and URL formatting
Practical applications
Real-World Use Cases
API Development
Encode parameters for REST APIs and GraphQL queries
/api/search?q=hello%20worldForm Submission
Encode form data before sending to servers
application/x-www-form-urlencodedQuery Strings
Build safe URL query parameters with special characters
?name=John%20Doe&city=New%20YorkOAuth Flows
Encode redirect_uri and state parameters
redirect_uri=https%3A%2F%2Fapp.com%2FcallbackTechnical reference
URL Encoding Standards
Understanding URL encoding standards is important for proper implementation:
| Standard | Year | Description | Space Encoding | Notes |
|---|---|---|---|---|
| RFC 3986 | 2005 | Modern standard for URI syntax | %20 | Current web standard |
| RFC 1738 | 1994 | Original URL specification | %20 | Deprecated but still referenced |
| application/x-www-form-urlencoded | HTML 2.0 | Form submission encoding | + | Used in HTML forms |
| RFC 2396 | 1998 | URI generic syntax update | %20 | Superseded by RFC 3986 |
Reference
Understanding URL Parts
Scheme
Protocol identifier
https://Not encoded
Host
Domain name
example.comNot encoded
Path
Resource location
/path/to/resourcePartially encoded
Query
Parameters
?key=value&foo=barFully encoded
Fragment
Page section
#sectionNot encoded
Practical examples
Common Encoding Examples
| Input | Encoded Output | Use Case |
|---|---|---|
Hello World | Hello%20World | Basic text with space |
john@example.com | john%40example.com | Email address |
https://example.com?q=test | https%3A%2F%2Fexample.com%3Fq%3Dtest | Full URL as parameter |
café | caf%C3%A9 | Unicode characters |
a+b=c | a%2Bb%3Dc | Mathematical expression |
100% complete | 100%25%20complete | Percentage sign |
Stay secure
URL Encoding Security Best Practices
Always Encode User Input
Never trust raw user input in URLs. Always encode before adding to query strings
Use HTTPS
URL encoding doesn't encrypt data. Always use HTTPS for sensitive information
Validate on Server
Client-side encoding isn't enough. Always validate and sanitize on the server
Avoid Double Encoding
Don't encode already-encoded URLs. This can cause errors and security issues
Use Consistent Encoding
Stick to one encoding standard (RFC 3986) across your application
Test with Special Characters
Always test URLs with spaces, ampersands, and unicode characters
Quick facts
URL Encoder at a Glance
Instant Encoding
Milliseconds processing
100% Private
Local browser processing
Mobile Friendly
Works on all devices
Browser Based
No installation needed
Pro tips
Tips for Best Results
Encode entire parameter values: Not just special characters, but the entire value
Avoid double encoding: Don't encode URLs that are already encoded
Use modern browsers: Chrome, Firefox, Safari, or Edge for best performance
Test with special characters: Always verify URLs with spaces, &, and unicode
Comparison
Why Choose AttachAD?
| Feature | AttachAD | Manual Encoding | Other Tools |
|---|---|---|---|
| Free to Use | — | ||
| Browser Based | — | ||
| No Installation | |||
| Mobile Friendly | — | ||
| Offline Support | — | ||
| Privacy (Local Processing) | — | ||
| No Registration | — | ||
| Character Reference | — | — | |
| One-Click Examples | — | — | |
| Copy to Clipboard | — |
FAQ
Frequently Asked Questions
Characters like spaces, &, ?, #, %, +, /, and non-ASCII characters should be encoded to ensure safe URL transmission. Reserved characters that have special meaning in URLs (like ?, &, =, #) must be encoded when used as data rather than URL syntax. Non-printable characters and characters outside the ASCII set also require encoding.
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Ready to encode or decode URLs?
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