What Is Base64 Encoding?
Base64 encoding converts binary data into a plain-text string using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It was originally designed to safely transmit binary data like images and files through channels that only support text, such as email (MIME).
Common Uses of Base64
- Data URIs — Embed images directly in HTML or CSS:
src="data:image/png;base64,..." - JSON APIs — Transmit binary data (images, files) inside JSON payloads
- Email attachments — MIME encoding uses Base64 for file attachments
- Authentication tokens — JWT headers and payloads are Base64-encoded
- Database storage — Store binary files as text in databases that don't support binary types
Is Base64 Secure?
No. Base64 is encoding, not encryption. Anyone can decode a Base64 string instantly — it provides zero security. Never use Base64 to hide sensitive information like passwords. If you need security, use proper encryption (AES, RSA, etc.).
How Much Larger Is Base64?
Base64 increases the size of data by approximately 33%. A 100 KB image encoded in Base64 becomes roughly 133 KB. This is a trade-off for compatibility when embedding binary data in text-based formats.
Frequently Asked Questions
What is Base64 encoding?
Base64 encoding converts binary data into printable ASCII text so it can be safely transmitted or stored in text-only systems.
Is Base64 the same as encryption?
No. Base64 provides no security — it is just a different representation of the same data and can be decoded by anyone instantly.