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🔐 URL Encoder/Decoder

A tool that encodes special characters for safe use in URLs or decodes encoded URLs back to original text.

📝 Input Text

✨ Result

💡 Examples

Original:
https://example.com/search?query=헬로 월드&lang=ko
Encoded:
https%3A%2F%2Fexample.com%2Fsearch%3Fquery%3D%ED%97%AC%EB%A1%9C%20%EC%9B%94%EB%93%9C%26lang%3Dko

URL encoding converts special characters into percent-encoded format for safe transmission in URLs. Use Encode to convert special characters, and Decode to restore the original text.

Key Features​

1. URL Encoding (Encode)​

Converts special characters, Korean, spaces, etc. to percent encoding format (%XX).

Example:

Original: https://example.com/search?query=hello world&lang=en
Encoded: https%3A%2F%2Fexample.com%2Fsearch%3Fquery%3Dhello%20world%26lang%3Den

2. URL Decoding (Decode)​

Converts percent-encoded URLs back to readable original text.

Example:

Encoded: hello%20world
Decoded: hello world

3. Convenient Features​

  • Swap Text: Quickly swap input and result
  • Copy: Copy result to clipboard
  • Clear: Clear all inputs at once

Why URL Encoding is Necessary​

Safe URL Transmission​

URLs have characters with special meanings:

  • / : Path separator
  • ? : Query start
  • & : Parameter separator
  • = : Key-value separator
  • # : Fragment

To transmit these characters as data, encoding is necessary.

Korean and Multilingual Text​

Original: https://example.com/search?keyword=hello
Encoded: https://example.com/search?keyword=hello

Korean or special characters cannot be used directly in URLs, so encoding is essential.

Usage Examples​

Web Development​

// Creating URL in JavaScript
const searchQuery = "hello world";
const encodedQuery = encodeURIComponent(searchQuery);
const url = `https://api.example.com/search?q=${encodedQuery}`;
// Result: https://api.example.com/search?q=hello%20world

API Calls​

# Original URL (won't work)
GET https://api.example.com/users?name=John Doe&age=30

# Encoded URL (works properly)
GET https://api.example.com/users?name=John%20Doe&age=30

Query Parameters​

# Search term with special characters
Original: search=C++ & Java
Encoded: search=C%2B%2B%20%26%20Java

Characters That Get Encoded​

Always Encoded Characters​

  • Space: → %20
  • Korean/Chinese: Each character encoded as multiple bytes
  • Special Characters: !, @, #, $, %, ^, &, *, (, ), =, +, [, ], {, }, etc.

Examples​

!     → %21
@     → %40
#     → %23
$     → %24
%     → %25
&     → %26
=     → %3D
+     → %2B
Space → %20

Use Cases​

🌐 Web Development​

  • Search Functionality: Convert user input to URL queries
  • API Calls: Encode GET request parameters
  • File Names: Handle file names with special characters

📧 Email Links​

<!-- mailto link with subject and body -->
<a href="mailto:test@example.com?subject=Hello&body=Inquiry">
<!-- After encoding -->
<a href="mailto:test@example.com?subject=Hello&body=Inquiry">

🔗 Social Media Sharing​

// Facebook share URL
https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fexample.com&quote=Great%20article

// Twitter share URL
https://twitter.com/intent/tweet?text=Amazing%20news&url=https%3A%2F%2Fexample.com

📊 Data Analysis​

  • Log Analysis: Interpret encoded URLs in web server logs
  • Tracking URLs: Interpret parameters from Google Analytics, etc.

Tips​

When to Encode?​

  • ✅ Query parameter values: ?search=needs encoding
  • ✅ Korean/special characters: name=John Doe
  • ✅ Spaces: query=hello world
  • ❌ Domain: https:// (already safe characters)
  • ❌ Path separators: /api/users (intentional separators)

Full URL vs Parameters Only​

// ❌ Wrong way: Encode entire URL
const wrong = encodeURIComponent("https://example.com/search?q=hello");
// Result: https%3A%2F%2Fexample.com%2Fsearch%3Fq%3Dhello

// ✅ Right way: Encode only parameter values
const query = encodeURIComponent("hello");
const correct = `https://example.com/search?q=${query}`;
// Result: https://example.com/search?q=hello

Beware of Double Encoding​

Original: hello
1st encoding: hello
2nd encoding: hello

// Don't encode the same text twice!

Usage by Programming Language​

JavaScript​

// Encoding
const encoded = encodeURIComponent("hello");
// Decoding
const decoded = decodeURIComponent(encoded);

Python​

from urllib.parse import quote, unquote

# Encoding
encoded = quote("hello")
# Decoding
decoded = unquote(encoded)

Java​

import java.net.URLEncoder;
import java.net.URLDecoder;

// Encoding
String encoded = URLEncoder.encode("hello", "UTF-8");
// Decoding
String decoded = URLDecoder.decode(encoded, "UTF-8");

PHP​

// Encoding
$encoded = urlencode("hello");
// Decoding
$decoded = urldecode($encoded);

FAQ​

Q: Which part of the URL should I encode? A: Only encode the values in query parameters. Don't encode the protocol (https://), domain, or path separators (/).

Q: Space is shown as both %20 and +, what's the difference? A: %20 can be used anywhere in the URL, while + represents space only in query parameters. Generally, using %20 is safer.

Q: I'm getting decoding errors. A: The input text may not be in proper URL encoding format, or it may already be decoded text. Please check the original encoded URL again.

Q: What happens if I encode an already encoded URL? A: Double encoding occurs, resulting in unintended results. For example, %20 becomes %2520. Only encode once.