URL Encoder / Decoder

What is URL Encoder / Decoder?

URL Encoder converts special characters in a string into their percent-encoded equivalents as specified by RFC 3986. It correctly handles reserved characters like &, =, ?, #, and spaces, replacing them with their %XX hex representations. The decoder reverses this process, converting percent-encoded sequences back to readable text. It also provides a full URL parser that breaks down query strings into individual key-value pairs.

Frontend developers building dynamic URLs, backend engineers parsing request parameters, and QA engineers debugging malformed URLs in test environments. The tool runs entirely in your browser — your data never leaves your device.

How to Use URL Encoder / Decoder

1. Paste or type the string you want to encode into the input field
2. Select encode mode for converting to percent-encoded output or decode mode for the reverse
3. Choose between encodeURIComponent (for parameter values) or encodeURI (for full URLs)
4. Review the transformed output which highlights changed characters
5. Copy the result to use in your URLs, API calls, or configuration files

Common Use Cases

• Encoding query parameter values that contain special characters like ampersands or question marks
• Decoding percent-encoded URLs from server logs or analytics reports for readability
• Preparing search strings for API calls where user input may include reserved URI characters
• Fixing broken links that have double-encoded characters from copy-paste errors
• Encoding file paths with spaces or Unicode characters for use in HTTP requests

Pro Tips

• Use encodeURIComponent for individual query parameter values — encodeURI leaves characters like & and = unencoded because it assumes a complete URL structure
• Spaces can be encoded as either %20 or + depending on context — %20 is correct for path segments while + is valid only in query strings under application/x-www-form-urlencoded
• Watch for double encoding — if you see %2520 instead of %20, the string was encoded twice and needs only one decoding pass

Why Use This Tool?

• Privacy-first: All processing happens locally in your browser. No data is transmitted to any server.
• No installation required: Works in any modern browser on desktop or mobile.
• Completely free: No account, no credit card, no usage caps.
• Fast and reliable: Powered by modern Web APIs for near-instant results.

Related Concepts

Learn more about related topics: RFC 3986, Percent-encoding, Query string, URI component.

Frequently Asked Questions