DataHub Tools URL Encoder Decoder

URL Encoder and Decoder

Local-first

Encode or decode URL components, query strings, and special characters locally in your browser.

What is URL Encoder Decoder?

Encode or decode URL components, query strings, and special characters locally in your browser.

  • Encode URL components safely
  • Decode percent-encoded strings
  • Copy clean query parameter output

How to use it

  1. Use Encode component for one query value, path segment, or parameter fragment.
  2. Use Encode full URL only when reserved URL separators must remain readable.
  3. Use Decode once on an encoded component and inspect the result before decoding again.
  4. Test the final URL in the target application to catch double encoding or server-specific rules.

Quick example

Example input

name=Ada Lovelace&city=Hong Kong

Expected output

name%3DAda%20Lovelace%26city%3DHong%20Kong

Encode parameter values separately when building a URL. Re-encoding percent signs can produce broken double-encoded values.

Best use cases

  • Encode query values for API calls and links.
  • Decode copied URL components during debugging.
  • Compare component encoding with full-URL encoding.

Reference standards and behavior

ECMAScript defines encodeURI, encodeURIComponent, and decodeURIComponent. The WHATWG URL Standard defines URL parsing and percent-encoding behavior used by web platforms.

Sources checked July 24, 2026. Standards can change; review the source pages before formal integration.

Notes

  • Component encoding and full-URL encoding preserve different characters.
  • A plus sign and %20 are not interpreted identically by every form or server parser.
  • The tool does not validate whether the destination URL is safe or trustworthy.

FAQ

When should I use Encode component?

Use it for one query value, parameter value, or path segment, including a full URL that will become an outer parameter value.

When should I use Encode full URL?

Use it only for an already complete URL when separators such as :, /, ?, &, and = must keep their URL meaning.

Why does Encode full URL leave & and = unchanged?

It uses encodeURI, which preserves reserved separators because they may structure the complete URL.

Why can decoding fail?

Malformed percent escapes or bytes that are not valid UTF-8 can make decodeURIComponent throw an error.

What is double encoding?

Encoding an existing percent sign again changes %20 to %2520 and can break the receiving system.

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