URL Encoder / Decoder

Encode and decode URLs and URL components. Highlights reserved characters and shows live preview.

Input
Output
Encoded URL will appear here…

What is URL Encoding?

Handling URLs correctly is critical when working with web applications, APIs, and query parameters. Improperly encoded URLs can break requests, cause data loss, or introduce security vulnerabilities. A URL Encoder converts unsafe or reserved characters into a percent-encoded format, making them safe for transmission over the internet. A URL Decoder reverses the process, converting encoded strings back into readable text.

—Broken query parameters: Special characters like & and = break query string parsing.
—Invalid API requests: Unencoded characters cause servers to reject or misinterpret input.
—Debugging encoded URLs: Logs and network tabs often show percent-encoded strings.
—Safe data transmission: Encoding guarantees data integrity across HTTP requests.

encodeURI vs encodeURIComponent

The two standard JavaScript encoding functions behave differently and are suited for different tasks. Choosing the wrong one is a common source of subtle bugs.

encodeURIComponent() — Component mode

Encodes all special characters including ? & = # /. Use this for individual query parameter values so they don't interfere with URL structure.

hello world&name=dev
→ hello%20world%26name%3Ddev

encodeURI() — Full URL mode

Encodes unsafe characters but preserves reserved URL characters like ? & = # /. Use this when encoding a complete URL while keeping its structure intact.

https://example.com/search?q=hello world
→ https://example.com/search?q=hello%20world

Key Features

✓Component encoding — encodeURIComponent() for query parameters and values
✓Full URL encoding — encodeURI() to encode complete URLs preserving structure
✓Instant decoding — decodeURIComponent() / decodeURI() with error handling
✓Live output — Result updates as you type — no submit button needed
✓Swap mode — Flip input and output instantly to reverse the operation
✓100% client-side — No data is ever sent to a server

How to Use the URL Encoder / Decoder

  1. 1Paste your input: Drop a URL, query string, or any text into the input panel.
  2. 2Choose a mode: Select Encode to percent-encode the input, or Decode to reverse it.
  3. 3Select encoding type: Use Component mode for query parameter values, or Full URL mode for complete URLs.
  4. 4Copy the result: The output updates instantly. Copy it with the copy button or use the Swap button to flip input and output.

Example

Input

https://example.com/search?query=hello world&category=dev tools

Output (Component encoded)

https%3A%2F%2Fexample.com%2Fsearch%3Fquery%3Dhello%20world%26category%3Ddev%20tools
Space
→
%20
?
→
%3F
=
→
%3D
&
→
%26

Common Use Cases

API Development

Encode query parameters before sending HTTP requests to avoid parsing errors on the server.

Debugging URLs

Quickly decode percent-encoded URLs from browser network tabs or application logs.

Handling User Input

Safely include user-generated content in URLs without breaking structure.

Form Submissions

Ensure special characters in form fields don't corrupt submitted data.

Security & Data Integrity

Prevent injection issues by always encoding untrusted input before embedding it in URLs.

OAuth & Redirects

Properly encode redirect_uri and other OAuth parameters to avoid authentication failures.

Benefits for Developers

  • →Prevents broken requests: Invalid characters in URLs cause 400 errors and silent data corruption.
  • →Faster debugging: Instantly decode opaque percent-encoded strings from logs and network traces.
  • →Standards compliance: Uses native JavaScript APIs — encodeURIComponent and encodeURI — for correct RFC-compliant output.
  • →Real-time preview: No submit button; results appear as you type.
  • →No setup required: Works in any browser — no Node.js, npm, or extensions needed.
  • →Secure by design: Client-side only. Sensitive tokens and credentials never leave your machine.

Frequently Asked Questions

What is URL encoding used for?

URL encoding converts characters that are unsafe or have special meaning in URLs into a percent-encoded format (e.g. space → %20). This ensures the URL is valid and interpretable by servers and browsers.

What is the difference between encodeURI and encodeURIComponent?

encodeURI() encodes a complete URL and preserves reserved characters like ?, &, =, and #. encodeURIComponent() encodes everything including those reserved characters, making it the right choice for individual query parameter values.

Is this tool safe to use?

Yes. All encoding and decoding happens directly in your browser using native JavaScript APIs. No data is transmitted to any server.

Can I encode large URLs?

Yes. The tool handles typical URLs and query strings without issues. Extremely long inputs may be limited by your browser, but standard use cases work smoothly.

Is this tool free?

Yes. The URL Encoder / Decoder on NexoraTools is completely free with no sign-up or restrictions.