TBToolbox
Encoding

URL Decoder

Turn a percent-encoded complete URL back into readable Unicode text while preserving its scheme and structural separators. Paste a URL containing sequences such as %20 or %C4%83 and receive the decoded form immediately. Decoding happens locally and does not test or open the URL.

Runs locally — files stay on your device
Quick answer

What does URL decoding do?

It converts valid percent triplets back to readable characters without opening or requesting the URL.

What URL decoding does

Percent decoding converts valid %XX byte triplets back to characters. For non-ASCII text, consecutive bytes are interpreted as UTF-8. Reserved separators must be parsed in context because decoding one can change the meaning of a URL.

How it works

The tool uses decodeURI, which reverses full-URI encoding but leaves encoded reserved delimiters protected where decoding them would alter structure. Invalid percent sequences produce an error instead of a partial result.

When to use it

  • Read a URL copied from logs or analytics.
  • Inspect international text represented by UTF-8 percent triplets.
  • Compare a browser-visible URL with its encoded request form.

When not to use it

  • Do not decode untrusted data and then execute it without validation.
  • Do not expect it to decrypt hidden information.
  • Do not use it for application/x-www-form-urlencoded plus signs.

Worked examples

Readable path

Input
https://example.com/summer%20sale
Expected output
https://example.com/summer sale

%20 becomes a space.

UTF-8 text

Input
https://example.com/c%C4%83utare
Expected output
https://example.com/căutare

Two encoded bytes reconstruct ă.

Protected delimiter

Input
https://example.com/a%2Fb
Expected output
https://example.com/a%2Fb

decodeURI protects an encoded slash because decoding it would change path segmentation.

Common mistakes

Expecting plus to become a space

decodeURI does not apply HTML form decoding rules. Correction: Handle form-urlencoded query data with the appropriate parser.

Decoding malformed triplets

A percent sign without two valid hexadecimal digits is invalid. Correction: Fix or remove the malformed sequence first.

Using decoded output without validation

Decoded delimiters or control data can affect downstream parsing. Correction: Validate each component before reuse.

Related operations and differences

URI Component Decoder

It decodes an isolated component, including escapes that a full-URI decoder may preserve.

URL Encoder

It performs the reverse transformation for complete URLs.

Limitations and privacy

  • It does not validate reachability, DNS, or HTTP status.
  • It follows decodeURI behavior, not form-urlencoded rules.

Processing uses browser APIs on this device; the entered content is not sent to the Toolbox server.

Frequently asked questions

Why was %2F not changed to a slash?

A slash is a reserved delimiter; full-URI decoding preserves escapes that would change URL structure.

Does decoding visit the URL?

No. It transforms only the pasted string.

Why does malformed input fail?

Every percent sign must begin a valid two-digit hexadecimal byte sequence.

Will plus signs become spaces?

No. That behavior belongs to form query encoding, not general URI decoding.

References