What Is Base64 Encoding?
Base64 converts binary data into ASCII text for safe transmission. Learn how it works.
Published 2026-03-01
In this guide
Short answer
Base64 represents binary data using a 64-character alphabet (A–Z, a–z, 0–9, +, /) with = padding, so it can be sent over text-only systems. It increases size by about 33%.
Common uses
Base64 appears in data URIs for images, email attachments, API auth tokens and embedding small files in JSON.
Important caveat
Base64 is encoding, not encryption. It is easily reversed, so never use it to protect secrets.