URL (Uniform Resource Locator) was introduced by Tim Berners‑Lee in the 1990s for the Web, using a human‑readable string to describe scheme/host/path/query/fragment. To avoid data characters being mistaken for delimiters (e.g., ? & # = /) and to handle spaces, non‑ASCII text and emoji, URLs convert such characters to %HH percent‑encoding (e.g., space→%20, “/” in a parameter value→%2F). In application/x‑www‑form‑urlencoded contexts, spaces may also be written as “+” (outside forms, %20 is recommended). URL encoding is a reversible formatting step used to keep links robust; it does not provide encryption or confidentiality.

No. Encoding is a reversible format conversion. Passwords, API keys and other secrets must be encrypted

Forms (application/x-www-form-urlencoded) use +, while RFC 3986 generally uses %20. This tool defaults to %20 for better compatibility; if you need +, use it in form contexts or replace manually

Encoded content contains %XX sequences (% followed by two hex digits, e.g., %E4%BD%A0). If you see many such sequences, it is already encoded; avoid encoding again

The URL standard allows only ASCII. Non‑ASCII text (e.g., accented letters, emoji) must be percent‑encoded (UTF‑8 bytes as %HH) for safe transmission