URL Encoder and Decoder Tool
Need to encode or decode a URL? Use this free online URL Encoder and Decoder to safely convert special characters into percent-encoded format and vice versa. Ideal for web developers, SEO specialists, and digital marketers.
Why Use Our URL Encoder and Decoder Tool?
All processing happens in your browser. No data is sent to servers or stored anywhere.
Instant encoding and decoding with one-click functionality. No waiting or processing delays.
Once loaded, the tool works without an internet connection. Perfect for developers on the go.
Supports all special characters, emojis, symbols, and international text encoding.
One-click copy to clipboard or download results as text files for easy sharing.
Smart error detection and helpful messages to guide you through any encoding issues.
Frequently Asked Questions
A URL encoder converts special characters into a percent-encoded format that can be safely transmitted over the internet. It's essential when adding URLs to query strings, APIs, or web forms.
Yes, this tool runs entirely in your browser. Your data is never sent to any server, stored, or tracked. Everything happens client-side for maximum privacy and security.
Use URL encoding when your URL contains special characters like spaces, &, ?, #, or non-ASCII characters. This ensures the URL works correctly in web browsers, APIs, and web applications.
Common characters that need encoding include spaces (%20), ampersands (%26), question marks (%3F), hash symbols (%23), plus signs (%2B), and most non-ASCII characters like emojis and international text.
Related Developer Tools
Also check out our other encoding and formatting tools
Complete URL Encoding Guide for Developers
Master URL encoding and decoding for web development, API integration, and data transmission.
Understanding URL Encoding (Percent-Encoding)
What is URL Encoding?
URL encoding (also called percent-encoding) is a mechanism to encode information in URLs by replacing special characters with percent signs (%) followed by two hexadecimal digits. This ensures that URLs remain valid and can be safely transmitted over the internet.
URLs can only contain certain ASCII characters. When you need to include special characters, spaces, or non-ASCII characters in URLs, they must be encoded to prevent conflicts with URL structure and to ensure proper transmission across different systems.
Why URL Encoding is Essential
- • Character Safety: Safely include special characters in URLs
- • Data Integrity: Prevent URL parsing errors and data corruption
- • Cross-Platform: Ensure URLs work across all systems and browsers
- • API Compatibility: Properly format parameters for REST APIs
- • Form Submissions: Handle user input with special characters
- • International Content: Support Unicode characters in URLs
Character Encoding Reference
Common Characters That Need Encoding
Reserved Characters
URL Structure Characters
Safe vs Unsafe Characters
Safe Characters (No Encoding Needed)
Context-Dependent Characters
Implementation Across Programming Languages
JavaScript/TypeScript
encodeURIComponent() - Recommended
// Encode query parameters and form data
const encoded = encodeURIComponent("Hello World!");
console.log(encoded); // "Hello%20World%21"
// Decode back to original
const decoded = decodeURIComponent(encoded);
console.log(decoded); // "Hello World!"encodeURI() - For Full URLs
// Encode full URLs while preserving structure
const fullUrl = "https://example.com/search?q=hello world";
const encoded = encodeURI(fullUrl);
console.log(encoded); // "https://example.com/search?q=hello%20world"Other Languages
Python:
from urllib.parse import quote, unquote
# Encoding
encoded = quote("Hello World!")
print(encoded) # "Hello%20World%21"
# Decoding
decoded = unquote(encoded)
print(decoded) # "Hello World!"PHP:
// Encoding
$encoded = rawurlencode("Hello World!");
echo $encoded; // "Hello%20World%21"
// Decoding
$decoded = rawurldecode($encoded);
echo $decoded; // "Hello World!"Real-World Applications and Best Practices
API Query Parameters
Safely pass user input and complex data through URL parameters for REST API calls.
/search?q=John%20Doe&city=New%20YorkForm Data Submission
Handle form submissions with special characters, spaces, and international content.
name=José%20García&email=user%40example.comSecure Data Transmission
Prevent URL injection attacks and ensure data integrity during transmission.
token=abc%3D%3D&redirect=%2FdashboardAdvanced Implementation Patterns
1. Building Dynamic URLs with Parameters
Construct URLs programmatically while handling special characters:
function buildApiUrl(baseUrl, params) {
const queryString = Object.entries(params)
.map(([key, value]) => `${encodeURIComponent(key)}=${encodeURIComponent(value)}`)
.join('&');
return `${baseUrl}?${queryString}`;
}
const url = buildApiUrl('https://api.example.com/search', {
query: 'Hello World!',
category: 'Books & Media',
limit: 20
});2. Handling International Content
Properly encode Unicode characters for global applications:
// Encoding international characters
const searchTerm = "München café";
const encodedTerm = encodeURIComponent(searchTerm);
console.log(encodedTerm); // "M%C3%BCnchen%20caf%C3%A9"
// URL with international domain
const url = `https://example.com/search?q=${encodedTerm}`;3. OAuth and Authentication
Handle OAuth redirect URLs and authentication parameters:
const redirectUri = encodeURIComponent('https://myapp.com/auth/callback');
const scope = encodeURIComponent('read:user user:email');
const authUrl = `https://github.com/login/oauth/authorize?client_id=abc123&redirect_uri=${redirectUri}&scope=${scope}`;Security Considerations and Best Practices
Security Guidelines
- • Input Validation: Always validate and sanitize user input before URL encoding
- • Double Encoding: Avoid encoding already-encoded URLs to prevent data corruption
- • Context Awareness: Use appropriate encoding for URL components (path vs query vs fragment)
- • Length Limits: Be aware of URL length limits (2048 chars for IE, 8192+ for modern browsers)
- • Sensitive Data: Never encode sensitive information like passwords in URLs
Common Pitfalls to Avoid
- • Wrong Function: Using encodeURI() for query parameters instead of encodeURIComponent()
- • Manual Encoding: Manually replacing spaces with + instead of %20 in modern contexts
- • Forgotten Decoding: Not decoding parameters on the server side
- • Character Set Issues: Mixing different character encodings in the same URL
- • Over-Encoding: Encoding characters that don't need encoding