CornerTools

URL Encoder & Decoder

Encode or decode URLs using standard percent encoding or form-style query encoding.

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URL Encoder & Decoder

This tool helps you encode and decode URLs so they can be safely used in browsers, APIs, and web applications. URL encoding converts special characters into a standardized percent-encoded format, while decoding reverses that process back into readable text.

URLs are not allowed to contain spaces or certain reserved characters in their raw form. Encoding ensures that data such as query parameters, paths, or form values are transmitted correctly without breaking the URL structure.

How URL Encoding Works

URL encoding replaces unsafe or reserved characters with a percent sign followed by their hexadecimal byte value. For example, a space becomes %20 under standard URL encoding.

Decoding performs the inverse operation, translating percent- encoded sequences back into their original characters. The exact behavior depends on whether standard URL encoding or form-style query encoding is used.

Inputs and Options Explained

The tool provides options to control how encoding and decoding are performed based on the context in which the URL is used.

  • Mode — Switch between Encode (plain text to URL-encoded form) and Decode (URL-encoded text back to readable form).
  • Encoding type — Choose between URL Component encoding (RFC 3986) and Form / Query String encoding.
  • Trim input — Removes leading and trailing whitespace before processing.
  • Preserve reserved characters — Prevents certain reserved URL characters from being encoded when required by specific APIs or routing rules.

Examples and Edge Cases

Standard URL component encoding converts spaces to%20, while form-style query encoding converts them to +. Using the wrong encoding type can lead to incorrect server-side parsing.

Decoding should only be applied once. Decoding an already decoded string can unintentionally alter valid percent sequences and corrupt the data.

Who Should Use This Tool

This tool is useful for anyone working with URLs, query strings, or web requests that include user-provided or dynamic data.

  • Developers building or debugging API requests
  • Frontend engineers handling query parameters
  • QA engineers testing URL-based workflows
  • Anyone inspecting encoded links or redirects

Related Concepts

URL encoding is one part of a broader set of data-encoding techniques used on the web.

  • Percent encoding — Encoding unsafe characters using hexadecimal values.
  • Query strings — Key-value pairs appended to URLs for data transfer.
  • Reserved characters — Characters with special meaning in URLs, such as ?, &, and /.

If your URLs contain encoded JSON or structured data, decoding them and inspecting the result with the JSON Formatter can make debugging easier. For encoded tokens or payloads, the Base64 Encoder & Decoder is often used alongside URL encoding.

Frequently Asked Questions

URL encoding (RFC 3986) encodes spaces as %20, while form-style encoding uses +. Form encoding is typically used for query strings and form submissions.
Usually only individual components such as query parameters or path segments should be encoded, not the entire URL at once.
Certain characters are considered safe or reserved and may be preserved depending on the selected options and encoding type.
Decoding is safe when applied to encoded input once. Decoding multiple times can corrupt valid percent-encoded sequences.
No. All encoding and decoding happens locally in your browser. Your input is never uploaded.