AlfennAI

URL Decoder

Decode percent-encoded URLs and query strings back to plain text.

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How it works

Percent-encoded URLs -- strings full of %20, %3A, %2F sequences -- are technically correct but hard for a human to read at a glance. This tool reverses that encoding using decodeURIComponent, turning a URL or query string back into its original, readable form.

This is useful when debugging a webhook payload, inspecting a redirect URL, or reading a log line where the URL was captured in its raw encoded form. Paste the encoded string and get back exactly what a browser would have sent before encoding.

Runs entirely in your browser; nothing you paste is transmitted anywhere.

Frequently asked questions

What happens with malformed input?

You'll see a clear error instead of a crash if the percent-encoding is malformed -- for example, an incomplete %-sequence at the end of the string.

Can I decode a full URL, not just a query string?

Yes -- decodeURIComponent works on any percent-encoded text, whether it's a full URL, just the query string, or a single parameter value.

Why does %20 turn into a space?

20 is the hexadecimal ASCII code for the space character, which isn't allowed unencoded in a URL -- this is the standard percent-encoding scheme (RFC 3986).

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