What's the difference between encodeURI and encodeURIComponent?

This is a critical JavaScript concept. 'encodeURI' encodes a full URL and does NOT encode reserved characters like '?', '&', '/', '#', which are necessary for the URL to function. 'encodeURIComponent' is used for a single part of a URL (like a query parameter) and encodes ALL reserved characters. 99% of the time, you want 'encodeURIComponent' for your data. Our tool uses the 'encodeURIComponent' logic for maximum safety.

Why do spaces sometimes show as '+' (plus) in URLs?

This is a legacy standard from old 'application/x-www-form-urlencoded' HTML forms. Technically, the modern standard (RFC 3986) dictates spaces should be '%20'. However, many servers still interpret '+' as a space in query strings. Our tool standardizes on '%20' for encoding, but our decoder correctly handles both '+' and '%20' as spaces.

URL Encoder / Decoder

A free online tool to percent-encode special characters or decode URL strings.

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Your Security Matters: Client-Side Processing

All operations happen in your browser.
Your data, keys, or passwords are never stored or sent to our servers.
We don't track or monitor your generated content.

What is URL Encoding (Percent-Encoding)?

URL encoding, also known as **percent-encoding**, is a standard (RFC 3986) for making strings web-safe. URLs can only contain a specific set of "unreserved" characters (A-Z, a-z, 0-9, -, _, ., ~).

Any other "reserved" or "special" characters must be encoded. This process replaces the special character with a percent sign (%) followed by its two-digit hexadecimal ASCII code.

Why encode URLs?

Spaces: A space is converted to %20 (or sometimes +) to prevent the URL from breaking.
Reserved Characters: Characters like /, ?, &, =, +, and % have special meanings in a URL (e.g., ? starts a query string). To send these characters as *data* (e.g., "a+b"), they must be encoded (a%2Bb) to avoid being misinterpreted by the server.
Non-ASCII Characters: Characters like ö or 😊 must be encoded (e.g., %C3%B6) to be transmitted correctly.

Our tool uses the JavaScript encodeURIComponent logic, which correctly encodes all necessary characters for maximum safety in URL parameters.

URL Encode/Decode Examples

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URL Encoding Best Practices

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encodeURIComponent vs. encodeURI

This is the most common pitfall for developers. encodeURI() is for encoding a *full* URL and will NOT encode reserved characters like ?, &, /. encodeURIComponent() is for encoding a *single parameter* (part of a URL) and WILL encode those characters. Our tool uses the encodeURIComponent logic, which is what you want 99% of the time.

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100% Client-Side & Secure

All URL encoding and decoding happens in your browser. No data (like sensitive API keys in parameters) is ever sent to our server. It's safe and private.

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SEO & Readability

For SEO, it's best to use human-readable keywords in your URL slugs (e.g., `/my-new-post`). While browsers can handle unencoded spaces or special characters, properly encoding them (like spaces to %20 or -) ensures maximum compatibility with all web crawlers and systems.