URL Encoder and Decoder Online - What Is URL Encoding?

URLs often contain spaces, symbols and special characters that cannot always be used directly. URL encoding converts these characters into a format that can safely be used in URLs. In this guide, you will learn what URL encoding and decoding mean, what values such as %20 represent and when URL encoding is useful.

What Is URL Encoding?

URL encoding is a method used to represent characters in a URL using percent-encoded values. It is also commonly called percent-encoding.

Certain characters have special meanings in URLs. Other characters, such as spaces and many non-ASCII characters, need to be represented in an encoded form when they are placed into specific URL components.

Simple example: A space can commonly be represented as %20 in a percent-encoded URL.

What Is URL Decoding?

URL decoding reverses percent-encoding. It converts encoded sequences back into their corresponding characters. 

Encoded:
Hello%20World

Decoded:
Hello World

URL encoding and decoding are often used together when applications build, send or process URLs.

Why Is URL Encoding Needed?

URLs have defined syntax and certain characters have reserved meanings. If arbitrary text is inserted into a URL without proper handling, the browser or server may interpret some characters differently from what the application intended.

Encoding helps represent data safely within the appropriate part of a URL.

What Does %20 Mean in a URL?

The sequence %20 is a percent-encoded representation of a space character in a URL. 

Hello World

becomes:

Hello%20World

The percent sign indicates that an encoded byte value follows. The hexadecimal value 20 corresponds to the space byte in the commonly used ASCII/UTF-8 representation.

Common URL Encoded Characters

Here are some commonly encountered percent-encoded characters:

  • Space → %20
  • ! → %21
  • # → %23
  • $ → %24
  • % → %25
  • & → %26
  • + → %2B
  • ? → %3F
  • = → %3D

The exact handling of a character can depend on which part of a URL it appears in and which URL-processing rules are being used.

Simple URL Encoding Example

Suppose a search query contains the text: 

best mobile phones

A percent-encoded representation can be: 

best%20mobile%20phones

The encoded value can then appear as part of a URL query parameter. 

https://example.com/search?q=best%20mobile%20phones

URL Encoding in Query Parameters

Query parameters are commonly used to send information to a web server. For example: 

https://example.com/search?q=hello

If the value contains spaces or other characters that require encoding, the value should be encoded appropriately. 

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

Applications should encode parameter values rather than manually replacing characters whenever possible.

Reserved and Unreserved Characters

URL syntax distinguishes between reserved characters and characters that can generally appear without percent-encoding in the appropriate URL component.

Characters such as :, /, ?, #, [, ], @, !, $, &, ', (, ), *, +, ,, ; and = can have reserved meanings depending on their position in a URL.

Characters considered unreserved include letters, digits, hyphen, period, underscore and tilde.

Important: A character being technically allowed in a URL does not always mean it should be inserted into every URL component without encoding. Context matters.

URL Encoding and UTF-8

Modern websites commonly use UTF-8 to represent text. Characters outside the basic ASCII range are represented through their UTF-8 bytes and then percent-encoded when required.

This allows URLs to represent text from many different languages. 

Example text:
café

Possible percent-encoded form:
caf%C3%A9

The exact encoded result depends on the UTF-8 byte representation of the characters.

URL Encoding vs HTML Encoding

URL encoding and HTML entity encoding are different techniques.

  • URL encoding: represents characters within URL components using percent-encoding.
  • HTML encoding: represents certain characters in HTML using character entities such as &.

Choosing the correct encoding method depends on where the data will be used.

URL Encoding vs Base64

URL encoding and Base64 solve different problems.

URL encoding is designed around URL syntax and percent-encoding. Base64 represents binary data using a text alphabet.

Neither should automatically be considered a security mechanism.

Working with Base64?

Read our Base64 Encoder and Decoder Guide or use the Base64 Encoder & Decoder .

How to Encode a URL Online

An online URL encoder can quickly convert text into a percent-encoded representation.

  1. Open the HoxTools URL Encoder & Decoder.
  2. Enter or paste the text or URL component.
  3. Select the encode option.
  4. Run the tool.
  5. Copy the encoded result.
Try the free tool:

Open HoxTools URL Encoder & Decoder

How to Decode a URL Online

URL decoding is useful when you receive a percent-encoded value and need to read the original characters.

  1. Open the HoxTools URL Encoder & Decoder.
  2. Paste the encoded URL or text.
  3. Select the decode option.
  4. Run the decoder.
  5. Review the decoded result.
Encoded:
HoxTools%20Free%20Online%20Tools

Decoded:
HoxTools Free Online Tools

URL Encoding in Web Development

Developers frequently work with URL encoding when building websites, APIs and web applications.

Common situations include:

  • Search parameters
  • Form submissions
  • API requests
  • Redirect URLs
  • Pagination parameters
  • Filter parameters
  • Links containing user-generated text
  • Passing values between web applications

URL Encoding in APIs

APIs often receive information through query parameters. Correctly encoding parameter values helps prevent reserved characters from being interpreted as URL syntax.

For example, an application might send: 

https://api.example.com/search?q=mobile%20phone

The server can decode the query parameter and use the original value: 

mobile phone

Common URL Encoding Mistakes

1. Encoding the Entire URL Incorrectly

A complete URL contains different components, and encoding every character of the complete URL can change its structure.

Developers should normally encode the individual value or URL component that needs encoding rather than blindly encoding the entire URL.

2. Double Encoding

Double encoding happens when a value is encoded more than once. 

Original:
Hello World

First encoding:
Hello%20World

Encoding the % again can produce:
Hello%2520World

This can cause unexpected results when the receiving application decodes the value.

3. Confusing Plus and %20

In application/x-www-form-urlencoded form data, a plus sign can represent a space. In other URL contexts, the plus sign may represent an actual plus character.

Because URL processing depends on context, applications should use the appropriate encoding method for the specific URL component or form format.

4. Manual Replacement of Characters

Manually replacing spaces and symbols can lead to incomplete or incorrect encoding. Programming languages provide standard URL encoding functions that are generally safer and more reliable.

URL Encoding and Security

URL encoding is not encryption. Encoding a value does not make confidential information secret.

Security tip: Do not put passwords, private keys or other sensitive secrets into URLs. URLs can be stored in browser history, logs, analytics systems, referrer information and other places depending on the application.

Can URL Encoding Make a URL Safe?

URL encoding can represent characters correctly within the appropriate URL component, but it does not automatically make a URL safe from every security problem.

Applications still need proper input validation, authorization, output handling and other security controls.

URL Encoding for International Languages

URLs can represent text from languages such as Urdu, Arabic, Chinese, Japanese and many others through Unicode and UTF-8 encoding.

When required, the UTF-8 bytes are represented using percent-encoded sequences.

Example: Unicode text may look much longer after percent-encoding because a single visible character can require multiple UTF-8 bytes.

When Should You Use a URL Encoder?

A URL encoder is useful whenever you need to safely represent text inside a URL component and want to avoid manually handling special characters.

It can be particularly helpful during API development, debugging, testing and web application development.

When Should You Use a URL Decoder?

A URL decoder is useful when a URL contains percent-encoded values and you need to inspect or understand the underlying text.

Developers can also use decoding while troubleshooting API requests, query strings and redirects.

HoxTools URL Encoder & Decoder

HoxTools provides a free online URL Encoder & Decoder for quickly encoding and decoding text used in URLs.

The tool can be useful for developers, students, website owners and anyone who needs to work with URL-encoded text.

Encode or decode now:

Use HoxTools URL Encoder & Decoder

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Frequently Asked Questions

What is URL encoding?

URL encoding, also called percent-encoding, represents certain characters in a URL using percent signs followed by hexadecimal byte values.

What does %20 mean in a URL?

%20 is the percent-encoded representation commonly used for a space character in a URL.

What is URL decoding?

URL decoding converts percent-encoded sequences back into their corresponding characters.

Is URL encoding encryption?

No. URL encoding is not encryption. Encoded values can generally be decoded easily.

What is the difference between URL encoding and Base64?

URL encoding represents characters using percent-encoding for URL syntax, while Base64 represents binary data using a text alphabet.

Why are spaces encoded as %20?

A space has the hexadecimal byte value 20 in ASCII and UTF-8, so its percent-encoded representation is commonly written as %20.

Can URL encoding handle non-English languages?

Yes. Unicode text can be represented using its UTF-8 bytes and percent-encoded when required.

What is double URL encoding?

Double encoding occurs when an already percent-encoded value is encoded again, which can turn characters such as % into %25 and produce unexpected results.

Is HoxTools URL Encoder & Decoder free?

Yes. The HoxTools URL Encoder & Decoder is available as a free online tool.

Conclusion

URL encoding is an important part of modern web development. It allows characters to be represented appropriately inside URL components and helps applications correctly transmit parameter values.

Understanding percent-encoding, decoding, reserved characters and UTF-8 can make it much easier to work with URLs and troubleshoot web requests.

Ready to encode or decode a URL?

Try the free HoxTools URL Encoder & Decoder now.