What Is URL Encoding?
URL encoding (also called percent-encoding) converts characters that are not allowed in URLs into a safe representation. Each unsafe character is replaced with a percent sign followed by its two-digit hexadecimal ASCII code.
For example:
- Space →
%20(or+in query strings) &→%26=→%3D#→%23- Chinese character 你 →
%E4%BD%A0(UTF-8 bytes encoded)
Decoding reverses this process, turning %20 back into a space and %E4%BD%A0 back into 你.
How to Use the URL Encoder Decoder
- Open DevKits' URL encoder decoder in your browser.
- Choose Encode or Decode mode using the toggle.
- Paste your text or URL into the input field.
- The output appears instantly — no button press required.
- Click Copy to grab the result.
Encode Example
Input: https://example.com/search?q=hello world&lang=中文
Output: https://example.com/search?q=hello%20world&lang=%E4%B8%AD%E6%96%87Decode Example
Input: https%3A%2F%2Fexample.com%2Fpath%3Fkey%3Dvalue
Output: https://example.com/path?key=valueKey Features
- Instant bidirectional conversion — encode and decode with no button press.
- Full URL vs component mode — encode an entire URL (preserving the
://and/structure) or encode just a query parameter value (where/and:are also escaped). - Unicode support — correctly encodes non-ASCII characters to their UTF-8 percent-encoded sequences.
- One-click copy — copy the result to your clipboard immediately.
- No data sent to a server — all encoding runs locally in JavaScript.
encodeURI vs encodeURIComponent
JavaScript offers two encoding functions, and knowing the difference is important:
encodeURI()— encodes a complete URL. It does not encode characters that are valid URL structural characters:: / ? # [ ] @ ! $ & ' ( ) * + , ; =encodeURIComponent()— encodes a URL component (like a query string value). It encodes almost everything except letters, digits, and- _ . ! ~ * ' ( ). Use this when encoding a value that will appear inside a query parameter.
DevKits' tool provides both modes so you can choose the right one for your situation.
Use Cases
Building Query Strings in APIs
When constructing API requests with dynamic parameters — user input, search queries, filter values — you must URL-encode each parameter value before including it in the query string to avoid breaking the URL structure.
Debugging Encoded URLs
Log files and network traffic captures often contain percent-encoded URLs that are hard to read at a glance. Paste the encoded URL into the decoder to see the human-readable version instantly.
Email and Social Media Links
When embedding a URL inside an email template or a social media post, spaces and special characters must be encoded. The encoder tool ensures your links work correctly across all clients and platforms.
Working with Non-ASCII Characters
Internationalized URLs (containing Chinese, Arabic, Japanese, or accented characters) must be percent-encoded. The tool handles UTF-8 encoding correctly, so you can confidently encode any Unicode text.
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Frequently Asked Questions
What is the difference between URL encoding and Base64 encoding?
URL encoding converts special characters to percent sequences so a string can be safely used in a URL. Base64 encoding converts binary data to a text representation using 64 printable ASCII characters — it is used for embedding binary content (images, files) in text contexts, not for URL safety.
Why does a space sometimes become + and sometimes %20?
In HTML form submissions (application/x-www-form-urlencoded), spaces are encoded as +. In strict percent-encoding (RFC 3986), spaces become %20. Modern APIs and URLs generally use %20. The DevKits tool uses %20 by default but offers a toggle for form-encoding mode.
Does URL decoding have security implications?
Yes. Double-encoding attacks involve encoding a character twice to bypass security filters. Servers and proxies should be careful about how many rounds of decoding they apply. Always decode URLs exactly once in your application code.
Can I encode a full URL including the protocol?
Yes, using "full URL" mode. This preserves the protocol (https://), slashes, domain, and path separators while encoding only the characters that are unsafe in their current position.
What characters are safe and do not need encoding?
Unreserved characters are always safe: uppercase and lowercase letters (A–Z, a–z), digits (0–9), hyphen (-), underscore (_), period (.), and tilde (~). All other characters should be percent-encoded when used in query parameter values.