URL Encoding Explained: Usage & Safety

Have you ever seen a URL filled with %20, %3F, and other strange characters? That’s URL encoding (also known as percent-encoding) in action. It’s the internet’s way of ensuring that valid URLs can be sent safely over any network.

What is URL Encoding?

URLs can only be sent over the Internet using the ASCII character set. If a URL contains characters outside this set (like spaces, emojis, or foreign language characters), they must be converted into a valid ASCII format.

URL encoding replaces unsafe ASCII characters with a % followed by two hexadecimal digits.

• Space: %20
• / (Slash): %2F
• ? (Question mark): %3F

You can test this yourself using our URL Encoder tool to instantly convert any text into a URL-safe format.

Why Do We Need It?

Imagine you want to send a search query for “Hello World!”. If you put that directly into a URL, the space character breaks the link because spaces are not allowed in URLs.

• Incorrect: https://example.com/search?q=Hello World!
• Correct: https://example.com/search?q=Hello%20World!

Browsers do this automatically for you most of the time, but as a developer, you often need to handle this manually when building APIs or redirecting users.

URL Encoding vs Base64

It’s important not to confuse URL encoding with other schemes like Base64.

• URL Encoding: Used specifically for making strings safe for use in URLs.
• Base64: Used for encoding binary data (like images) into text. You can try our Base64 Encoder tool to see the difference.

Common Pitfalls

Double Encoding

One common bug is encoding a string twice.

1. Hello World -> Hello%20World
2. Hello%20World -> Hello%2520World (The % sign itself gets encoded as %25)

Encoding the Entire URL

You should usually only encode the values of query parameters, not the entire URL string. Encoding the protocol (https://) or the path separators will break the link entirely.

Conclusion

URL encoding is a fundamental part of the web. Whether you are dealing with form submissions, API parameters, or simply sharing links, understanding percent-encoding prevents broken links and security issues.

Try our free URL Encoder to practice and inspect how your text is transformed!