🔗 URL Encoder / Decoder
Encode text to URL-safe format or decode percent-encoded URLs back to readable text.
What is this tool?
A URL encoder and decoder is a developer utility that converts text between its readable form and URL-safe percent-encoded format. URLs can only contain a limited set of characters from the ASCII character set, so any character outside this safe range must be encoded as a percent sign followed by two hexadecimal digits. For example, spaces become percent 20 or plus signs, and characters like ampersand, equals, question mark, and hash must be encoded when they appear in parameter values to avoid confusing the URL parser. This encoding is essential when constructing query strings, building API requests, embedding data in URLs, or handling international characters in web addresses. Chinese, Japanese, Korean, Arabic, and other non-Latin characters all require encoding to be safely transmitted in a URL. On the decoding side, if you receive a URL with encoded characters and need to read the original text, the decoder reverses the process. Developers working with web APIs, redirect URLs, tracking parameters, or form submissions use URL encoding daily. This tool makes the process instant and supports both encoding and decoding in a single interface.How it works
The URL encoder and decoder uses built-in JavaScript functions to perform the conversion. For encoding, it applies encodeURIComponent to the input text, which converts all characters except letters, digits, and the characters hyphen, underscore, period, exclamation mark, tilde, asterisk, apostrophe, and parentheses into their percent-encoded form. For decoding, it applies decodeURIComponent, which reverses the encoding by converting percent-encoded sequences back to their original characters. The tool handles Unicode characters correctly by encoding them as UTF-8 byte sequences in percent-encoded form. When decoding, it properly interprets multi-byte UTF-8 sequences. Error handling is included for malformed input, such as invalid percent-encoded sequences, and the tool displays a helpful error message instead of crashing. All operations run locally in your browser with no server communication.How to use
- Paste or type the text you want to encode or decode into the input text area.
- To encode text into URL-safe format, press the Encode button. Special characters will be converted to percent-encoded form.
- To decode percent-encoded URLs back to readable text, press the Decode button. Encoded sequences will be converted back to their original characters.
- Review the output in the result area and copy it using the copy button.
- If you see an error, check that you are using the correct operation. Encoding works on any text, but decoding requires valid percent-encoded input.
Frequently Asked Questions
Frequently Asked Questions
What characters does URL encoding affect?
URL encoding converts any character that is not a letter, digit, or one of the unreserved characters hyphen, underscore, period, tilde into percent-encoded form. Common characters that get encoded include spaces, ampersands, equals signs, question marks, hash symbols, slashes, and all non-ASCII characters including Chinese, Japanese, Korean, and accented Latin characters.
What is the difference between encodeURI and encodeURIComponent?
encodeURIComponent encodes everything including characters that have special meaning in URLs like slashes, question marks, and ampersands. encodeURI preserves those URL-structural characters and only encodes truly unsafe characters. This tool uses encodeURIComponent, which is the correct choice for encoding query parameter values where structural characters should also be encoded.
Can it handle international characters?
Yes. The tool correctly encodes Unicode characters including Chinese, Japanese, Korean, Arabic, Cyrillic, and accented Latin characters by converting them to their UTF-8 byte representation in percent-encoded form. For example, the Chinese character for middle becomes percent E4 percent B8 percent AD.
What happens if I try to decode invalid input?
The tool detects malformed input such as incomplete percent sequences or invalid hexadecimal digits and displays a clear error message. This prevents silent data corruption. Fix the input and try again. Common issues include truncated percent sequences or typos in the encoded text.
Tips & Advice
When building URLs with query parameters, always encode the parameter values but not the structural characters like equals signs and ampersands that separate parameters. If you are constructing a redirect URL that contains another URL as a parameter, encode the inner URL completely. For API development, encode all user-provided content that goes into URL parameters to prevent injection attacks and ensure correct parsing. When debugging URL issues, decode the URL first to see what the original values were before encoding. Remember that plus signs in query strings can represent spaces in form-encoded data but not in path segments, so be aware of the encoding standard being used. All processing happens locally in your browser.