URL encoder & decoder

What it does

Use the URL decoder to turn a percent-encoded link back into readable text, or the encoder to prepare text for a query string or a path. Encoding follows the same rules as the browser's encodeURIComponent and encodeURI, with the choice explained next to each option. Non-ASCII characters are encoded as UTF-8 bytes, so a rupee sign becomes %E2%82%B9. A checkbox handles the form convention of plus signs for spaces. When the text contains a query string, the parameters are listed decoded in a table, which is the quickest way to read a long tracking or search URL.

How to use it

1. Choose Encode or Decode.
2. Paste the text. For encoding, pick whether it is a single value for a query string or a complete URL.
3. Tick "Treat + as a space" if the text came from or is going into an HTML form.
4. Copy the result, and check the parameter table to confirm each key and value came through as intended.

How to read the result

The escapes card counts percent sequences. Encoding the query value web design & development as a component gives web%20design%20%26%20development, four escapes: three spaces and one ampersand. Had you used the whole-URL mode, the ampersand would have stayed, and a server would have read it as the start of a new parameter named development. That is the most common URL encoding bug.

The parameter table shows the decoded keys and values of everything after the question mark. A link with utm_source=newsletter&page=2 lists two rows; an empty value shows as "(empty)". A row whose key looks like half of the previous value means an unescaped ampersand upstream.

Output length versus input tells you how much a value grows. A 20-character address with spaces and commas becomes about 30 characters, which matters when URLs approach the limits of some older systems around 2,000 characters.

Related: build clean paths with the URL slug generator. Query handling of this kind is routine in web app development.