Base64
Best for arbitrary binary → compact text. Used in APIs, email MIME, data URIs, and JWT payloads. ~33% size overhead.
Hexadecimal
Each byte becomes two hex digits (0–9, A–F). Human-readable for hashes and debugging but 100% size overhead — twice as long as raw bytes.
URL (percent) encoding
Encodes unsafe URL characters as %XX. Designed for text in URLs, not efficient for large binary blobs. Use base64 when embedding files; use percent-encoding for query string text.