Component mode or full-URL mode?

Use component mode (encodeURIComponent) when you are encoding a single piece that goes inside a URL - a query-string value, a path segment, a token - because it escapes the separators like &, =, ?, / and # so they cannot be mistaken for structure. Use full-URL mode (encodeURI) when you have a whole URL and only want to escape illegal characters like spaces while leaving the :// and ? and & intact. Encoding a complete URL with component mode by mistake is a very common bug.

Why did my space become %20 or +?

Percent-encoding represents a space as %20. The + form for a space is specific to application/x-www-form-urlencoded - HTML form submissions - not to URLs in general. This tool produces %20, which is correct for query-string values and path segments. If a system expects form-encoding, it will treat %20 and + equivalently on decode.

Is anything uploaded?

No. Encoding and decoding use the browser built-ins and run entirely on your machine - nothing you type is sent to a server.

Free tool · Runs in your browser · Nothing uploaded

URL encode & decode.

Percent-encode text for a URL or decode it back — component mode for query values and path segments, full-URL mode that keeps ://, ?, and & intact. Two-way and live.

Text

Full-URL mode (encodeURI)

Encoded

Escape the value, not the structure

The whole game with URL encoding is keeping a value from being mistaken for structure. An ampersand inside a search term has to become %26 or it splits your query string into two parameters; a slash in an ID has to be escaped or it looks like another path segment. Component mode escapes those separators; full-URL mode leaves them alone because in a complete URL they are the structure. Pick the wrong one and you either break a working URL or silently corrupt a value.

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