URL encode and decode
The classic trap: encode a whole link with the wrong function and it stops working. Here you pick what you're encoding and the right function is used — no guessing.
Runs entirely in your browser. Nothing is uploaded or stored.
Encode turns text into %XX form; decode turns it back.
This is the part people get wrong: encoding a whole URL as a component breaks it.
FAQ
What's the difference between the two scopes?
A parameter value (component) also escapes / : ? & = # — that's what you want inside a query string. A whole URL keeps those characters intact, which is what you want for a full link.
Why did my encoded link stop working?
Almost always this: the whole URL was encoded as a component, so its / and ? became %2F and %3F and the server saw one long filename.
Is anything sent to a server?
No. It's plain string work in your browser.