URL Encoder/Decoder
Data is processed securely within your browser and not sent to any server.
What is a URL Encoder/Decoder?
A URL Encoder/Decoder is an online tool that converts characters that cannot be used directly in a URL — such as Korean text, spaces, and special characters — into percent-encoded format (%XX), and decodes them back into human-readable text. It supports both encodeURIComponent mode for encoding query parameter values and encodeURI mode for preserving the full URL structure. ToolVill's URL Encoder/Decoder runs 100% in your browser — your URLs are never sent to an external server.
Key Features
- Real-Time Conversion: Encoding and decoding results appear instantly as you type — no button click needed.
- Encoding Mode Selection: Choose between encodeURIComponent for query parameter values and encodeURI for preserving the full URL structure.
- Space Handling Option: Select whether spaces are decoded from %20 or +, supporting both standard URLs and HTML form-encoded data (application/x-www-form-urlencoded).
- Error Detection & Protection: Invalid % sequences (URIError) are caught immediately without crashing the app. The Swap function is automatically disabled on error to prevent data corruption.
- Fully Local Processing: All URL data is processed only within your browser's memory and is never transmitted externally.
When Should You Use It?
- When a URL containing Korean text or special characters appears broken and needs to be fixed or regenerated
- When encoding query parameter values that contain spaces, &, or = for API requests
- When handling application/x-www-form-urlencoded data where + must be treated as a space
- When decoding percent-encoded query strings like %EA%B0%80 to verify their actual values in web logs or analytics tools
- When safely encoding or decoding URLs that contain security tokens or API keys
Frequently Asked Questions (FAQ)
What is the difference between encodeURI and encodeURIComponent?
encodeURI is used for encoding a full URL and leaves URL-structural characters (:, /, ?, &, =) untouched. encodeURIComponent is used for encoding individual parts of a URL — such as query parameter values — and encodes nearly all special characters including & and =. For API parameters and query string values, encodeURIComponent is the standard choice.
Why does Korean text make URLs so long?
URL standards only allow alphanumeric characters and a limited set of special characters. Korean characters are encoded in UTF-8 as 3 bytes each, and each byte is represented as %XX, meaning a single Korean character can expand to up to 9 characters in a URL. For example, 가 becomes %EA%B0%80.
What is the difference between + and %20?
Both represent a space, but in different contexts. %20 is the standard URL encoding per RFC 3986, while + is used to represent spaces in HTML form data (application/x-www-form-urlencoded). This tool's space handling option lets you decode both formats correctly.
Is my URL sent to a server?
No. ToolVill's URL Encoder/Decoder processes everything locally inside your browser. URLs containing security tokens or personal information can be used safely — nothing is transmitted externally.