What is a URL Encoder / Decoder?
A URL encoder converts special characters in a string into percent-encoded format so they can be safely included in a URL. URLs can only contain a limited set of ASCII characters — letters (A–Z, a–z), digits (0–9), and a handful of safe symbols (-._~). All other characters — including spaces, ampersands, equals signs, non-ASCII letters, and Unicode characters — must be encoded as a percent sign followed by two hexadecimal digits (e.g., a space becomes %20, an ampersand becomes %26). A URL decoder reverses this process, converting percent-encoded sequences back to readable characters.
URL encoding is essential in web development: query string parameters that contain user input must be encoded before being appended to a URL to prevent breaking the URL structure. This matters for search queries, API calls, OAuth tokens, redirect URLs, form submissions, and any other scenario where dynamic data is embedded in a URL. Our tool implements JavaScript's native encodeURIComponent() and decodeURIComponent() functions, which correctly handle the full Unicode character range and follow RFC 3986 encoding rules.
How to Use the URL Encoder / Decoder
- Paste or type your text or URL into the input field.
- Click Encode URL to percent-encode special characters, or Decode URL to convert percent-encoded sequences back to plain text.
- Use the Swap button to move the output back into the input field for chained operations.
- Click Copy to copy the output to your clipboard.
Why Use Our URL Encoder / Decoder?
- 100% Free — Encode and decode unlimited URLs at no cost.
- No Registration — No account needed, works instantly.
- Browser-Based — Uses JavaScript's native encodeURIComponent() — your data never leaves your device.
- Swap Function — Quickly swap input and output for chained encode/decode operations.
- Error Handling — Clear error messages when invalid percent-encoded sequences are detected during decoding.
Frequently Asked Questions
encodeURI() encodes a complete URL and does NOT encode characters that are valid URL structural characters: : / ? # [ ] @ ! $ & ' ( ) * + , ; =. encodeURIComponent() encodes a URL component (like a query parameter value) and DOES encode those structural characters. Use encodeURI for full URLs and encodeURIComponent for parameter values within query strings. Our tool uses encodeURIComponent, which is correct for encoding data that goes inside a URL.
Both %20 and + are used to represent a space in URLs, but in different contexts. %20 (percent-encoding) is the correct representation in path segments and is defined in RFC 3986. The + sign represents a space only in the application/x-www-form-urlencoded encoding used in HTML form submissions and some query strings. encodeURIComponent() always uses %20, which is universally correct. Some older systems use + in query strings, but %20 works everywhere.
Whenever you include dynamic data in a URL — especially in query string parameters. Common cases: search queries (https://example.com/search?q=hello+world should be ?q=hello%20world), redirect URLs passed as parameters (?redirect=https%3A%2F%2Fexample.com), API keys and tokens in query strings, user-submitted form values appended to URLs, and OAuth state parameters. Most HTTP libraries and frameworks handle this automatically, but when building URLs manually you must encode parameter values.
Yes. Unicode characters (Arabic, Chinese, Cyrillic, emoji, accented letters, etc.) are encoded using UTF-8 byte sequences in percent-encoded format. For example, the German "ü" (U+00FC) encodes to %C3%BC. Modern browsers and web frameworks handle international characters automatically and display decoded URLs in the address bar for readability, but the actual request is made with percent-encoded bytes.