URL Encoder & Decoder Tool
This browser-based tool converts Japanese text and special characters in URLs to percent-encoding format (%XX) and vice versa. Adopts RFC 3986-compliant UTF-8 encoding, perfect for API development, search query creation, and sharing Japanese URLs. No registration required for instant use, and no data is transmitted externally.
What You Can Do
The URL Encoder & Decoder Tool converts Japanese text and special characters in URLs to safe percent-encoding format (%XX), and vice versa, all within your browser. Perfect for API development debugging, search query creation, and sharing Japanese URLs. Adopts RFC 3986-compliant UTF-8 encoding.
- ✅ Encode: Convert Japanese text and symbols like "検索" → "%E6%A4%9C%E7%B4%A2"
- ✅ Decode: Restore percent-encoded strings to original text
- ✅ RFC 3986 Compliant: Accurate conversion following URL standard specifications
Easily encode and decode URLs. Safely convert URLs containing Japanese text or special characters.
💼 Use Cases
- API Development & Debugging - Properly encode URL parameters containing Japanese text or symbols
- URL Sharing - Convert Japanese URLs to alphanumeric format for safe transmission
- Query Parameter Creation - Convert search keywords to URL format
- Browser Address Bar Analysis - Convert encoded URLs to readable format
- Web Development Learning - Perfect for understanding URL encoding mechanisms
How to Use
📌 Basic Usage
Simply enter the string you want to encode or decode and click the corresponding button to execute the conversion.
💡 What is URL Encoding
URL encoding (percent-encoding) is a method to convert characters that cannot be used in URLs or reserved characters into a safe format. It is necessary when using multibyte characters like Japanese or special characters in URLs.
⚙️ Conversion Examples
- Japanese: "検索" → "%E6%A4%9C%E7%B4%A2"
- Space: "hello world" → "hello%20world"
- Symbols: "?&=" → "%3F%26%3D"
🔍 Common Use Cases
- Search Parameters: Including Japanese text in search queries
- API Calls: Including special characters in URL parameters
- Link Sharing: Sharing URLs containing Japanese text
- Debugging: Checking the content of encoded URLs
📝 Notes
- URL encoding uses UTF-8 character set
- Be careful not to encode already encoded strings (double encoding)
- Encode only necessary parts, not the entire URL
💼 Application Scenarios
- Web API query parameter creation
- Form data URL transmission
- Decoding encoded URLs
- Japanese URL conversion
- Development and debugging work
📚 Technical Explanation of URL Encoding
📖 About RFC 3986 - Basics of URL Standards
RFC 3986 (Uniform Resource Identifier: Generic Syntax) is the official standard specification by IETF (Internet Engineering Task Force) that defines the syntax of URLs and URIs. It was published in 2005 as a revision of RFC 2396 from 1998.
🔹 Reserved Characters Defined in RFC 3986
The following characters have special meanings in URLs and must be encoded when used as data:
:Separator between scheme and host (e.g.,https://)/Path separator (e.g.,/tools/url-encoder/)?Query string start (e.g.,?q=search)#Fragment identifier start (e.g.,#section)[ ] @ ! $ & ' ( ) * + , ; =Subcomponent delimiters
🔹 Unreserved Characters
The following characters can be used without encoding:
- Alphanumeric:
A-Z a-z 0-9 - Symbols:
- _ . ~(hyphen, underscore, period, tilde)
💡 This tool performs RFC 3986-compliant encoding and decoding. Reserved characters used as data are automatically converted to percent-encoding.
🔧 How Percent-Encoding Works
Percent-encoding is a technique to convert characters that cannot be used in URLs into hexadecimal ASCII code representation. The conversion is performed in the following steps:
📌 Encoding Steps (Example: "検索")
- Convert to UTF-8 byte sequence
- "検" → UTF-8:
E6 A4 9C(3 bytes) - "索" → UTF-8:
E7 B4 A2(3 bytes)
- "検" → UTF-8:
- Convert each byte to percent sign + hexadecimal
E6→%E6A4→%A49C→%9CE7→%E7B4→%B4A2→%A2
- Result: "検索" →
%E6%A4%9C%E7%B4%A2
📌 Decoding Steps (Reverse Conversion)
- Convert hexadecimal numbers after percent signs to byte values
- Interpret byte sequence as UTF-8 and restore to original string
⚠️ Warning: Re-encoding already encoded strings results in "double encoding" and cannot be decoded correctly. Example: Re-encoding %E6%A4%9C → %25E6%25A4%259C (% becomes %25)
🔤 Character Encoding and Mojibake Prevention
The most important aspect of URL encoding is unified Character Encoding. Mojibake (garbled text) occurs when different character encodings are used for encoding and decoding.
🌐 Common Character Encodings
| Encoding | Description | URL Encoding |
|---|---|---|
| UTF-8 | Current web standard. Represents all Unicode characters in 1-4 bytes | ✅ Recommended (Used by this tool) |
| Shift_JIS | Legacy Japanese character code. 1-2 bytes | ⚠️ Not recommended (compatibility issues) |
| EUC-JP | Japanese code used in UNIX | ⚠️ Not recommended (now rare) |
| ISO-8859-1 | For Western European languages. No Japanese support | ❌ Cannot use for Japanese |
🛡️ Best Practices to Prevent Mojibake
- Unify with UTF-8: Match HTML
<meta charset="UTF-8">with server settings (Content-Type) - Use UTF-8 for URL encoding: All modern URL encoders including this tool adopt UTF-8
- Avoid double encoding: Don't call JavaScript's
encodeURIComponent()multiple times - Use same character code for decoding: Always decode UTF-8 encoded URLs with UTF-8
📌 This tool always uses UTF-8, ensuring 100% compatibility with modern web applications and APIs. Only when interacting with legacy Shift_JIS-based systems is server-side character code conversion required.
What is the URL Encoder/Decoder?
The URL Encoder/Decoder is a free online tool that converts Japanese characters and special characters in URLs to percent-encoded format and vice versa.
Who is this for?
Developers adding Japanese text to URL parameters, anyone checking the contents of encoded URLs, engineers building API request URLs with correct encoding, and people formatting URLs for sharing via email or chat.
Key Features
- One-click toggle between encoding and decoding
- Full Unicode support with UTF-8 for all languages
- Completely free with no registration required
- All processing is done in your browser - no data is sent to any server
FAQ
URL encoding (percent-encoding) is a method to convert Japanese text and special characters that cannot be used in URLs into safe "%XX" format strings. For example, "検索" is converted to "%E6%A4%9C%E7%B4%A2". It uses RFC 3986-compliant UTF-8 encoding.
Yes, you can convert URLs containing Japanese and multibyte characters to percent-encoding format. The tool also has a decode function to restore encoded URLs back to the original Japanese text. Real-time conversion is supported.
Double encoding occurs when you encode an already encoded string again. For example, "%E6" becomes "%25E6". To prevent this, check whether the string is already encoded before encoding it.
No, all processing is done in your browser. Your input data is never sent to a server.
It's completely free with no usage limits. No user registration is required.
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