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Base64 Encoder/Decoder
Encode and decode Base64 strings
What is a Base64 Encoder/Decoder?
Encodes binary data or text to Base64 and decodes it back - used in APIs, email attachments, data URIs, and JWT tokens.
How It Works
Converts every 3 bytes of binary data to 4 ASCII characters using a 64-character alphabet. Encoded data is approx 33% larger.
Example
"Hello World" becomes "SGVsbG8gV29ybGQ=". Data URIs embed images: "data:image/png;base64,iVBOR..." directly in HTML.
Pro Tips
- Base64 is encoding, not encryption - it provides zero security by itself.
- JWT tokens use Base64URL (URL-safe variant with - and _ instead of + and /).
- Data URIs reduce HTTP requests but increase HTML file size - use only for small icons.
- Base64 encoded passwords in HTTP Basic Auth headers always require HTTPS.
FAQ
Is Base64 encryption?▼
No - it is encoding. Anyone can decode it instantly. Use AES or RSA for actual security.
What is Base64URL?▼
URL-safe variant replacing + with - and / with _. Used in JWTs and URL query parameters.
Why does Base64 end with "=="?▼
Padding characters to make output length a multiple of 4 characters.
What are data URIs?▼
Base64-encoded file embedded directly in HTML or CSS as "data:media-type;base64,..."