What does the URL Encoder and Decoder do?
Use this tool when you need a browser utility that applies percent encoding to URL components or full URLs and can inspect query strings. It accepts plain text, an encoded component, a full URL, or a query string and returns encoded text, decoded text, or JSON query parameters. Results are deterministic for the same input except where cryptographic randomness, current time, or a live provider response is part of the task.
Component mode and full-URL mode are not interchangeable
Use component mode for a path segment, key, or parameter value. Use full-URL mode only when a complete URL already contains structural separators that must remain readable.
How do you use it?
- Choose whether the input is one component, a complete URL, or a query string.
- Paste the value into Input; conversion runs immediately when the text or operation changes.
- Inspect the encoded text or parsed query JSON, then copy or download it.
Worked example
Encode one query-parameter value
Input
hello world & teaOutput
hello%20world%20%26%20teaEncode component escapes spaces and the ampersand so the value cannot be mistaken for a query separator.
Common errors and fixes
| Symptom | Likely cause | Fix |
|---|---|---|
| Decode component reports a malformed URI sequence. | A percent sign is not followed by two hexadecimal digits or the bytes are not valid UTF-8. | Correct the incomplete escape instead of repeatedly decoding the value. |
| A full URL loses its separators after encoding. | Encode component was used on the whole URL. | Use Encode full URL to preserve :, /, ?, #, and other structural delimiters. |
Important behavior of URL Encoder
Use component mode for one parameter value; full-URL mode intentionally preserves URL separators.
Standards and implementation references
- WHATWG URL Standard (opens in a new tab)Defines URL parsing, percent encoding, and query behavior.
- MDN — encodeURIComponent() (opens in a new tab)Explains the browser API used for component encoding.
Frequently asked questions about URL Encoder
Does the URL Encoder upload my input?
No. Processing runs in the current browser tab, and the page does not send tool input to a KitLumi processing endpoint.
What input does the URL Encoder accept?
It accepts plain text, an encoded component, a full URL, or a query string. The workspace checks the input and reports malformed or unsupported values before it produces a result.
What does the URL Encoder produce?
It produces encoded text, decoded text, or JSON query parameters. Copy and download controls appear when the output format supports them.
What limitation should I know?
Use component mode for one parameter value; full-URL mode intentionally preserves URL separators.
What changed?
Added Component encoding, Full URL encoding, Malformed-sequence errors, Query-string parsing, responsive controls, explicit runtime disclosure, and tested browser output.