What is the difference between Full URL and Single value mode?

Full URL mode (encodeURI/decodeURI) keeps : / ? & = # working as link structure and only fixes unsafe characters. Single value mode (encodeURIComponent/decodeURIComponent) encodes those characters too (%26, %3D, %3F), which is what one query value needs so its own & or = cannot split the link.

Why did decoding say the percent-encoding is invalid?

There is a broken percent sign in the text: a trailing %, a short %2, a non-hex %ZZ, or bytes that are not valid UTF-8. The tool explains the problem instead of guessing a half-decoded result.

Is URL encoding encryption or security?

No. Percent-encoding is transport formatting that anyone can reverse instantly. It hides nothing, so never put a password, API key or token in a URL expecting encoding to protect it.

Is anything uploaded?

No. Conversion runs in your browser tab with the built-in encodeURI/encodeURIComponent functions. Nothing is uploaded, stored or shared.

URL-encoder — Hele Link of Losse Waarde, Gratis

Gratis URL-encoder en -decoder. Codeer een hele URL met encodeURI of één losse waarde met encodeURIComponent en decodeer beide kanten op, met duidelijke fouten bij ongeldige procentreeksen. UTF-8-veilig, volledig lokaal: niets geüpload. Coderen is geen versleuteling.