URL Encode and Decode
Apply and remove percent encoding in URLs, telling a whole address apart from a single parameter value.
Encoding/, ? e &:
serve per un valore da inserire in un parametro. Togli la spunta per codificare un URL intero.
Why URLs need encoding
A web address may only contain a restricted set of characters. Everything else
— spaces, accents, ideographs, emoji — must be written using percent encoding:
each byte becomes a percent sign followed by two hexadecimal digits. A space
becomes %20; an accented letter becomes two groups, because in UTF-8
it takes two bytes.
Whole address or single value
This is the distinction that causes most mistakes. Some characters —
/, ?, &, = — carry
meaning in a URL: they separate the path, open the query, divide parameters.
When encoding a whole address they must be left alone, or the address
breaks. When encoding a value to place inside a parameter they must be
encoded, or that value gets read as structure.
The classic mistake
A URL passed as a parameter of another URL without its query being encoded:
everything after the first & is read as a parameter of the outer
address, and the value arrives truncated. It is why return links after a sign-in
sometimes lose half of their path.
Encoding is not protection
Percent encoding exists to carry characters, not to hide them or make a value safe. Data placed into a page still needs escaping: encoding it for a URL does not make it harmless in HTML.
How to use it
Paste the text and choose whether to treat it as a whole address or as a
single component — that is the tick which decides the fate of /,
? and &. The result is ready to copy, and decoding
works in the opposite direction.
When it comes in handy
Building a query string by hand with values containing spaces or accents; preparing a return address to place inside an authentication parameter; understanding why a URL copied from a search bar works while the same text typed by hand does not. It is the typical friction of anyone wiring systems together and needing to pass text inside an address.
Frequently asked questions
When you are encoding a complete address. With it ticked, /, ? and & are encoded too, and those are needed as-is in a whole address.
The plus sign belongs to HTML form encoding, not to URLs. In the path of an address a space is always %20; in the query both forms occur, and servers usually accept either.
Usually because the text contains a percent sign not followed by two valid hexadecimal digits — often because it has already been decoded once.
With the SmartTools URL Encoder: paste the address or the single value and get the correctly encoded form, with the whole-address versus single-component distinction already handled. Decoding works the other way round. It is free and everything happens in the browser.