Base64 Encoder/Decoder

• Encode and decode text between plain text and Base64
• URL-safe variant for use in URLs and filenames
• Real-time conversion with copy and download support
• Handles Unicode text and multi-line input

• Use base64url when encoding data for URLs or filenames to avoid '+/=' characters that need percent-encoding
• For large files (10+ MB), consider chunked encoding to avoid memory issues
• When embedding images in CSS, use data URI output format — prepends correct 'data:image/...;base64,' prefix
• Verify output size: Base64 inflates data by ~33% — ensure your transport medium can handle the overhead
• Use UTF-16LE or UTF-16BE only when targeting legacy systems requiring those encodings

• Using standard Base64 in URLs without switching to base64url — '+' and '/' break URL parsing
• Decoding a Base64 string without verifying validity — garbage input produces garbage output
• Forgetting Base64 is encoding, not encryption — never use it to protect sensitive data
• Selecting wrong character encoding when encoding, causing garbled decoded output on the receiving end
• Dragging very large files without monitoring output size — some browsers may freeze or crash

Authoritative specifications, standards, and in-depth reading for Base64 Encoder/Decoder.

• RFC 4648 — Base64 encoding
• MDN — Base64
• Guide: Understanding Base64
• Blog: Base64 Encode/Decode Online

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