PHP URL Encoding and Decoding: urlencode(), urldecode(), rawurlencode()

PHP URL Encoding and Decoding

URL encoding converts unsafe characters in a URL into a safe format. This is needed when a URL contains spaces, special characters, search keywords, product names, redirect URLs, or query string values.

In PHP, the commonly used URL encoding and decoding functions are urlencode(), urldecode(), rawurlencode(), and rawurldecode(). PHP also provides http_build_query() to build query strings safely without joining parameters by hand.

This tutorial explains when to use each function with simple PHP examples.

Quick Answer

Use urlencode() for query string values. Use rawurlencode() for URL path segments.

• urlencode() converts spaces to +.
• rawurlencode() converts spaces to %20.
• urldecode() reverses urlencode().
• rawurldecode() reverses rawurlencode().

Why URL Encoding Is Important

URLs support only a limited set of characters. Problems happen when a value contains spaces, symbols, Unicode text, or reserved URL characters.

For example, this URL is invalid because it contains spaces:

https://example.com/search.php?q=mobile phone

After encoding, the URL becomes safe:

https://example.com/search.php?q=mobile+phone

Encoding helps prevent broken links and malformed query strings.

According to the RFC 3986 URL specification, reserved characters inside URLs must be encoded correctly.

Using urlencode() in PHP

The urlencode() function encodes a string for use inside a query string.

<?php

$keyword = "mobile phone";

$encoded = urlencode($keyword);

echo $encoded;
?>

Output:

mobile+phone

Now let us build a full URL.

<?php

$keyword = "wireless mouse";
$category = "computer accessories";

$url =
    "https://example.com/search.php?q=" .
    urlencode($keyword) .
    "&category=" .
    urlencode($category);

echo $url;
?>

Output:

https://example.com/search.php?q=wireless+mouse&category=computer+accessories

This is useful when sending search keywords, form values, redirect URLs, or API parameters through a query string.

You can also read the related PHPpot tutorial on
getting URL parameters in PHP.

Using urldecode() in PHP

The urldecode() function converts an encoded URL value back to normal text.

<?php

$encoded = "mobile+phone";

$decoded = urldecode($encoded);

echo $decoded;
?>

Output:

mobile phone

This is commonly used when reading query string values from a URL.

urlencode() vs rawurlencode()

Both functions encode URLs, but they are used for different purposes.

Use rawurlencode() when encoding filenames, slugs, folder names, or URL paths.

<?php

$fileName = "annual report 2026.pdf";

echo rawurlencode($fileName);
?>

Output:

annual%20report%202026.pdf

This output is more suitable for clean URL paths.

Using rawurldecode()

The rawurldecode() function decodes values encoded using rawurlencode().

<?php

$encoded = "annual%20report%202026.pdf";

echo rawurldecode($encoded);
?>

Output:

annual report 2026.pdf

Building Query Strings Safely with http_build_query()

Many developers manually concatenate query parameters. This can easily break when values contain spaces or special characters.

PHP provides http_build_query() to build query strings safely.

<?php

$params = [
    "q" => "wireless keyboard",
    "sort" => "price low to high",
    "page" => 2
];

$queryString = http_build_query($params);

echo $queryString;
?>

Output:

q=wireless+keyboard&sort=price+low+to+high&page=2

You can append this query string to a URL.

<?php

$url = "https://example.com/products.php?" . $queryString;

echo $url;
?>

This approach is cleaner and safer than manually joining parameters.

PHP documentation for http_build_query() explains additional options and encoding behavior.

PHP urlencode and rawurlencode example output

Common URL Encoding Examples

Encode Redirect URLs

When passing a redirect URL as a parameter, always encode it properly.

<?php

$redirectUrl = "https://example.com/account.php?tab=orders";

$loginUrl =
    "https://example.com/login.php?redirect=" .
    urlencode($redirectUrl);

echo $loginUrl;
?>

Output:

https://example.com/login.php?redirect=https%3A%2F%2Fexample.com%2Faccount.php%3Ftab%3Dorders

Encode User Input Before Sending to APIs

URL encoding is commonly used while sending search terms to APIs.

<?php

$city = "New York";

$apiUrl =
    "https://api.example.com/weather?city=" .
    urlencode($city);

echo $apiUrl;
?>

Encode Unicode Characters

PHP encoding functions also support Unicode characters.

<?php

$text = "தமிழ் language";

echo urlencode($text);
?>

Output:

%E0%AE%A4%E0%AE%AE%E0%AE%BF%E0%AE%B4%E0%AF%8D+language

Common Mistakes and Fixes

Encoding the Full URL

This is a common mistake:

<?php

$url = "https://example.com/search.php?q=mobile phone";

echo urlencode($url);
?>

This encodes the entire URL including : and /, which is usually not correct.

Instead, encode only the parameter values.

Double Encoding

Do not encode the same value twice.

<?php

$value = "mobile phone";

$encoded = urlencode($value);

echo urlencode($encoded);
?>

Output:

mobile%2Bphone

The second encoding changes the + character into %2B.

Using urlencode() for URL Paths

For URL paths, prefer rawurlencode().

Good:

/files/annual%20report.pdf

Less suitable:

/files/annual+report.pdf

Security Considerations

URL encoding improves URL safety, but it is not a security protection by itself.

• Do not treat URL encoding as input validation.
• Validate and sanitize user input separately.
• Escape output correctly when displaying decoded values in HTML.
• Do not blindly trust redirect URLs from user input.

If you are working with form input, you can also read the PHPpot guide on
preventing SQL injection in PHP.

Developer FAQ

What is the difference between urlencode() and rawurlencode()?

urlencode() converts spaces into +. It is mainly used for query strings. rawurlencode() converts spaces into %20 and is better for URL paths.

Does PHP automatically decode query string values?

Yes. Values inside $_GET are automatically decoded by PHP.

Should I encode database values before storing them?

No. Store the original value in the database. Encode only when building URLs.

Can urlencode() encode special characters?

Yes. It encodes reserved characters like spaces, ampersands, slashes, question marks, and Unicode characters.

Download Source Code

The downloadable project contains:

• URL encoding examples
• URL decoding examples
• rawurlencode() examples
• http_build_query() demo
• Simple styled demo page
• Setup instructions

Download the PHP URL Encoding and Decoding Source Code

Function Reference Summary

Conclusion

PHP provides simple and reliable functions for URL encoding and decoding.

For most applications:

• Use urlencode() for query parameters
• Use rawurlencode() for URL paths
• Use http_build_query() to safely build query strings
• Use decoding functions only when required

Correct URL encoding prevents broken links, malformed requests, and query string issues. It also makes your PHP applications more reliable when handling user input, redirects, API requests, and multilingual text.