Question 1

What's the difference between Component and Full URI mode?

Accepted Answer

Component mode uses encodeURIComponent/decodeURIComponent, which escapes every character with special meaning in a URL — including & = ? / : , — so it's safe for a single query-string value. Full URI mode uses encodeURI/decodeURI, which leaves those structural characters alone since they're expected to appear in a complete URL.

Question 2

Why didn't Full URI mode encode my & or = characters?

Accepted Answer

That's expected — Full URI mode assumes you're encoding an entire URL, where & and = already have meaning (separating query parameters). Switch to Component mode if you're encoding a single value that will be inserted into a query string.

Question 3

Why did decoding fail?

Accepted Answer

The input contains an incomplete or invalid % escape sequence (for example %zz or a trailing % with no hex digits after it) — check for a copy-paste error or double-encoded text.

Question 4

What does batch mode do?

Accepted Answer

Batch mode treats each line of the input as a separate value and encodes or decodes them independently, which is useful for processing a list of query-string values at once instead of one at a time.

Question 5

Is my input sent anywhere?

Accepted Answer

No — encoding and decoding use JavaScript's built-in encodeURIComponent/decodeURIComponent/encodeURI/decodeURI functions, running entirely in your browser.

URL Encoder & Decoder

Frequently asked questions