URL Encoder & Decoder

Free URL Encoder/Decoder – Convert URLs for Web Use Instantly

Introduction

Need to encode or decode URLs for web use? Our URL Encoder/Decoder Tool instantly converts special characters in URLs to percent-encoded format and back. Perfect for web developers, API integration, and anyone working with query parameters, form data, or web addresses.

This free tool is essential for creating valid URLs, passing data in query strings, and ensuring proper URL formatting. No manual conversion required – just paste your URL or text and encode or decode instantly.

What is URL Encoding?

URL encoding (also called percent-encoding) converts characters into a format that can be transmitted over the Internet. It replaces unsafe ASCII characters with a "%" followed by two hexadecimal digits representing the character's ASCII code.

Why URL Encoding Matters

URL encoding serves critical purposes:

Valid URLs

URLs can only contain certain characters (A-Z, a-z, 0-9, and a few special characters). Everything else must be encoded.

Data Transmission

Pass data safely in query strings, form submissions, and API requests without breaking the URL structure.

Special Character Handling

Characters like spaces, &, =, ?, #, and / have special meaning in URLs and must be encoded when used as data.

International Characters

Non-ASCII characters (é, ñ, 中文) must be encoded for universal compatibility.

Common URL Encoding Examples

Understanding frequently encoded characters:

Spaces and Punctuation

• Space → %20 (or + in query strings)
• ! → %21
• " → %22
• # → %23
• $ → %24
• % → %25
• & → %26

Reserved Characters

• + → %2B
• / → %2F
• : → %3A
• = → %3D
• ? → %3F
• @ → %40

International Characters

• é → %C3%A9
• ñ → %C3%B1
• 中 → %E4%B8%AD

When to Use URL Encoding

URL encoding is essential in these scenarios:

Query Parameters

• Search Queries: example.com/search?q=hello%20world
• Filter Parameters: site.com/products?category=shoes%26boots
• User Input: Any user-provided data in URLs

Form Submissions

• GET form data in URLs
• application/x-www-form-urlencoded POST data
• Contact form parameters

API Requests

• RESTful API parameters
• OAuth redirect URLs
• Webhook URLs
• API authentication tokens

Social Media Sharing

• Facebook share URLs
• Twitter intent URLs
• LinkedIn share parameters
• Email mailto links

URL Structure and Encoding

Understanding which parts of URLs need encoding:

URL Components

Full URL: https://example.com:8080/path/page?key=value&foo=bar#section

• Protocol: https:// (never encoded)
• Domain: example.com (special encoding for international domains)
• Port: :8080 (never encoded)
• Path: /path/page (encode special chars only)
• Query: ?key=value&foo=bar (encode values)
• Fragment: #section (encode if needed)

What to Encode

Always encode: Query parameter values, form data, user input

Sometimes encode: Path segments with special characters

Never encode: Protocol, domain, port, URL structure characters (://?&#)

How to Use the Tool

Encoding and decoding is simple:

To Encode

Step 1: Paste your text or URL
Step 2: Click "Encode"
Step 3: Copy the encoded result
Step 4: Use in your URL or query string

To Decode

Step 1: Paste URL-encoded text
Step 2: Click "Decode"
Step 3: Copy the readable text
Step 4: Use the decoded content

URL Encoding vs. HTML Encoding

Understanding the difference:

URL Encoding

Purpose: Make characters safe for URLs
Example: Space → %20
Use: Query strings, form data, API requests

HTML Encoding

Purpose: Display special characters in HTML
Example: < → <
Use: HTML content, preventing XSS

Common Use Cases

URL encoding applications across development:

Web Development

• Build search functionality with query parameters
• Create shareable URLs with filters
• Handle form submissions via GET
• Generate dynamic links

API Integration

• Encode API request parameters
• Build OAuth redirect URLs
• Create webhook endpoints
• Pass authentication tokens

Marketing and Analytics

• UTM parameter tracking
• Campaign URL builders
• Social media share links
• Email tracking parameters

E-commerce

• Product filter URLs
• Search result pages
• Affiliate tracking links
• Coupon code parameters

Best Practices

Professional URL encoding strategies:

Encode User Input

Always encode user-provided data before adding to URLs. Never trust user input to be URL-safe.

Use Built-In Functions

Most programming languages have URL encoding functions:

• JavaScript: encodeURIComponent()
• PHP: urlencode() or rawurlencode()
• Python: urllib.parse.quote()
• Java: URLEncoder.encode()

Encode Values, Not Structure

Only encode the data values, not the URL structure characters like ?, &, =

Double Encoding

Avoid encoding already-encoded URLs. Check if encoding is needed first.

Common Mistakes to Avoid

Don't fall into these URL encoding traps:

Encoding the Entire URL

Wrong: Encoding https://example.com/page
Result: https%3A%2F%2Fexample.com%2Fpage (broken!)
Right: Only encode query values

Forgetting to Encode

Wrong: /search?q=hello world
Problem: Space breaks the URL
Right: /search?q=hello%20world

Using + for Spaces

Context: + works in query strings but %20 is universal
Best Practice: Use %20 for consistency

Not Decoding on Server

Problem: Receiving %20 instead of spaces
Solution: Always decode URL parameters on the server

Programming Language Examples

URL encoding in popular languages:

JavaScript

const encoded = encodeURIComponent("hello world");
const decoded = decodeURIComponent("hello%20world");

PHP

$encoded = urlencode("hello world");
$decoded = urldecode("hello%20world");

Python

from urllib.parse import quote, unquote
encoded = quote("hello world")
decoded = unquote("hello%20world")

Java

String encoded = URLEncoder.encode("hello world", "UTF-8");
String decoded = URLDecoder.decode("hello%20world", "UTF-8");

Security Considerations

URL encoding and security:

Prevent Injection Attacks

Encoding user input prevents malicious URLs and injection attacks.

Validate After Decoding

Always validate decoded data on the server. Don't trust client-side encoding alone.

Open Redirect Prevention

Validate redirect URLs even after decoding to prevent open redirect vulnerabilities.

SQL Injection

URL encoding doesn't prevent SQL injection. Use parameterized queries.

Special Cases

Handling unique URL encoding scenarios:

Plus Sign (+)

In query strings, + represents a space. To use literal +, encode as %2B.

Forward Slash (/)

In paths, / is a separator. In query values, encode as %2F.

Ampersand (&)

Separates query parameters. In values, encode as %26.

Equals Sign (=)

Separates keys from values. In values, encode as %3D.

International Domain Names (IDN)

Handling non-ASCII domain names:

Punycode

International domains use Punycode encoding:
Example: münchen.de → xn--mnchen-3ya.de

IRI vs. URI

IRI: Internationalized Resource Identifier (readable)
URI: Uniform Resource Identifier (encoded)

Performance Considerations

Efficient URL encoding:

Cache Encoded URLs

For static URLs, encode once and cache the result.

Lazy Encoding

Only encode when necessary, not preemptively.

Batch Processing

When encoding multiple parameters, process efficiently.

Privacy and Security

Your data is completely safe:

• No Data Storage: We never save your URLs or text
• Client-Side Processing: All encoding happens in your browser
• No Account Required: Use anonymously
• Secure Connection: All data transmission is encrypted

Mobile and Cross-Device Usage

Our tool works perfectly on all devices:

• Responsive design for smartphones and tablets
• Touch-optimized interface
• Works offline once loaded
• No app installation needed
• Perfect for on-the-go encoding

Conclusion

URL encoding is a fundamental web development skill that ensures data transmits correctly in web addresses. Whether you're building search functionality, integrating APIs, creating shareable links, or handling form submissions, our free URL encoder/decoder makes it instant and effortless.

With instant encoding and decoding, you have everything you need to create valid, functional URLs. No downloads, no registration, and complete privacy. Bookmark this page and use it whenever you need to encode or decode URLs. Start building better web applications today!