What does URL encoding do?
Some characters have a special meaning in a web address. A question mark starts a query, an ampersand separates parameters and a hash introduces a fragment. Percent encoding represents characters as escaped byte values, so a piece of text can be used without accidentally changing that structure.
Should I encode a whole URL or one value?
Choose URL component for an individual parameter value or path component. It encodes separators as part of that value. Choose Whole URL when you want to preserve the structure of an existing address. For example, encoding the value “tea & coffee” differs from encoding an entire search-page URL.
Why do some spaces become + and others %20?
Form-style encoding represents a space with a plus sign. This tool’s component mode uses %20. In form mode, a literal plus is encoded as %2B, so it stays distinct from a space. Select the matching mode when decoding, because a plus sign is not automatically a space in every URL context.
What causes an invalid escape error?
A percent sign must be followed by a valid byte escape, and those bytes must form valid text for this tool. A truncated value or mixed encoding can produce an error. Decode one layer at a time; “Use result as input” lets you inspect each step instead of repeatedly decoding without checking.
Read the encodeURIComponent documentation, or try our HTML entity tool when the value contains & or <.