URL Encoding Tips — Avoid Common Mistakes

URL Encoding Tips

URL encoding seems simple, but it often leads to mistakes. Here are the key tips.

Tip 1: Only Encode Parameter Values

Do not encode the entire URL. Only encode query parameter values, leaving the URL structure intact.

Tip 2: Space Is %20 or +

In the URL path, a space is encoded as %20. In form bodies (application/x-www-form-urlencoded) it is encoded as +. Do not confuse the contexts.

Tip 3: Do Not Double-Encode

Double encoding is a common mistake. The & character becomes %26, and if encoded again — %2526. Always check your input data.

Tip 4: Account for UTF-8

Cyrillic and other Unicode characters are first converted to UTF-8 bytes, then each byte is encoded separately.

Tip 5: Use encodeURIComponent

In JavaScript, use encodeURIComponent() for encoding parameters, not encodeURI(). They encode different sets of characters.

Tip 6: Check the URL Length

Encoded URLs can become very long. Most browsers support URLs up to 2048 characters. For long data, use POST requests.

See also: Base64 Encoding, HTML Encoding, Binary Text