🔐 Base64 Encoder / Decoder

The Base64 Encoder / Decoder converts arbitrary text between raw form and Base64 — a widely-used encoding that represents any byte sequence using only 64 printable ASCII characters. Base64 is how binary data gets embedded inside JSON, JWT tokens, data URIs (data:image/png;base64,…), Basic HTTP authentication headers, and countless other places where a transport layer only accepts text. It is an encoding, not an encryption — anything Base64 can be decoded by anyone.

How to Use This Tool

Paste text into the input, press Encode to see the Base64 output, or paste Base64 and press Decode to see the original text. The tool uses standard browser Base64 APIs and handles UTF-8 correctly, so non-ASCII text (accents, emoji, Chinese) round-trips through encode → decode without loss.

SEO Best Practices

Use Base64 when a system genuinely can't carry raw bytes — otherwise it wastes ~33% of the payload size for no benefit. Never treat Base64 as a way to hide sensitive data; anyone with a decoder (like this one) can read it in one click. When embedding an image as a data URI, keep the file small: large base64 images bloat HTML/CSS and hurt caching.

Example

Encoding "Hello, world!" produces "SGVsbG8sIHdvcmxkIQ==" — 13 bytes become 20 characters of ASCII, plus padding. Decoding it returns the original string exactly.

Common Mistakes to Avoid

Don't send passwords or API keys as Base64 thinking that adds security — it doesn't. Don't truncate Base64 strings (they need their padding "="); a chopped-off string may still decode partially and produce corrupted output. Don't confuse Base64 with URL-safe Base64 (which uses "-" and "_" instead of "+" and "/") — they're similar but not interchangeable without a small character swap.