generators Client-Side Processing

URL Encoder / Decoder

Encode query parameters into percent-encoded strings (%20, %3F, %26) or decode them back to readable text.

Quickly percent-encode URL parameters or decode encoded web links with instant swap and clipboard copy.

Interactive URL Encoder / Decoder

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How to Use URL Encoder / Decoder

  1. Paste your raw text or encoded URL into the editor box.
  2. Select 'URL Encode' to percent-encode characters or 'URL Decode' to restore plain text.
  3. Use the Swap button to invert the input and output whenever needed.
  4. Copy the output with a single click for use in your API calls or web addresses.

About & Key Features of URL Encoder / Decoder

The URL Encoder & Decoder transforms text strings into percent-encoded URI components and reverses percent-encoded query parameters back into human-readable text. In web architecture (RFC 3986), query string components must escape non-alphanumeric and reserved characters into `%XX` hexadecimal escape sequences to prevent routing issues and parameter corruption.

Key Capabilities

  • Full URI component percent-encoding (`encodeURIComponent`) and decoding (`decodeURIComponent`)
  • Real-time encoding and decoding modes with instant error detection for malformed sequences
  • One-click 'Swap' button to quickly reverse input and output
  • One-click clipboard copy for encoded or decoded strings

Tips for Best Results

  • Use this tool to encode parameter values like search queries, redirect links, or JSON payloads before adding them to query strings.
  • Click the swap button to instantly decode what you just encoded to verify round-trip accuracy.
  • Common percent-encoded characters include spaces (`%20`), question marks (`%3F`), ampersands (`%26`), and slashes (`%2F`).

Common Use Cases & Practical Applications

1. Marketing UTM Parameter & Query String Encoding

Percent-encode spaces, ampersands, and special characters inside URL parameters to prevent broken tracking links.

Example: Encoding `campaign=summer sale & discounts` into `campaign=summer%20sale%20%26%20discounts`.

2. OAuth Redirect URI & Callback Sanitization

Encode complex callback URLs containing query strings so they can be passed safely as parameter values to identity providers.

Example: Encoding `https://app.example.com/oauth?client=1` into `https%3A%2F%2Fapp.example.com%2Foauth%3Fclient%3D1`.

3. Decoding Obfuscated Web Addresses & Analytics Links

Decode percent-encoded strings (%20, %2F, %3F, %3D) found in server access logs or deep tracking links back into readable URLs.

Example: Decoding a complex Google Ads tracking URL to read the original landing page destination.

Frequently Asked Questions

What is percent-encoding in URLs?

Percent-encoding (also known as URL encoding) replaces non-permitted characters with a percent sign (`%`) followed by two hexadecimal digits representing the character's UTF-8 byte value (e.g. a space becomes `%20`).

How does the tool handle URI characters?

The tool utilizes standard `encodeURIComponent` for encoding and `decodeURIComponent` for decoding, converting spaces to `%20` and escaping reserved characters like `?`, `&`, `/`, and `#` so they can be safely passed inside query strings.

Why do spaces sometimes appear as `%20` and other times as `+`?

Standard RFC 3986 URI encoding specifies `%20` for spaces. The `+` sign for spaces originated in the `application/x-www-form-urlencoded` specification used by legacy HTML form submissions.

Can this tool decode malformed URL strings with broken percent escapes?

Yes. If a percent sign is followed by non-hexadecimal characters, the decoder alerts you to the exact malformed sequence so you can fix it.

Is my URL data logged on your servers?

No. All URI encoding and decoding runs in local client-side JavaScript.