URL Encoder/Decoder

Introduction

Every URL you see in a browser address bar is subject to a strict set of allowed characters. Spaces, ampersands, hash symbols, quotation marks, and hundreds of other characters cannot appear in a URL as-is — they'd break the URL structure or be misinterpreted by the server. URL encoding (also known as percent-encoding) converts these unsafe characters into a safe format.

This URL Encoder/Decoder converts text both ways: encode raw text into a URL-safe format, or decode a percent-encoded URL back into human-readable text. Instant results in your browser — no server round trips.

Technical & Concept Breakdown

URL encoding (percent-encoding) replaces unsafe characters with a % followed by the two-digit hexadecimal representation of the character's UTF-8 byte value.

Examples:

• Space: %20 (or + in form encoding)
• &: %26
• =: %3D
• #: %23
• @: %40
• /: %2F (when encoding data, not URL structure)

In JavaScript:

// Encode — safe for query string values
encodeURIComponent('hello world & more') 
// → 'hello%20world%20%26%20more'

// Decode
decodeURIComponent('hello%20world%20%26%20more') 
// → 'hello world & more'

encodeURIComponent vs encodeURI:

• encodeURI encodes a full URL — it leaves structural characters (:, /, ?, &, =) untouched
• encodeURIComponent encodes everything including structural characters — use this for individual query parameter values

Decoding: decodeURIComponent reverses the process. If an encoded URL contains %20, it returns a space.

Real-World Use Cases

Developers: When building URLs with dynamic query parameters, encode each parameter value with encodeURIComponent() before concatenating. This tool lets you test what the encoded output looks like.

API Testing: POST request bodies in application/x-www-form-urlencoded format use percent-encoding. Encode your test data manually before pasting it into API clients like Postman.

Web Scraping: Encoded URLs are common in scraped data. Decode them to get the human-readable form of URLs and link targets.

Email Marketing: UTM parameter values containing spaces or special characters need encoding in tracking URLs. Verify encoding before deployment.

Debugging: A server returns a 400 Bad Request — check if a query parameter contains unencoded special characters that are confusing the server's URL parser.

Best Practices & Optimization Tips

**Always encod...