Question 1

What is Base64?

Accepted Answer

Base64 An encoding method that uses 64 ASCII characters to represent binary data. Core functions include:
            
                Resolving binary data transmission issues in text-based protocols (e.g. HTTP, XML)
                Converting non-printable characters to safe text format for transmission
                Widely used in:
                    
                        Web image embedding (data URI)
                        Email attachment encoding
                        API authentication tokens (JWT)
                        Binary data storage in databases

Encoding principle: Every 3 bytes (24 bits) of binary data is divided into 4 6-bit units, each mapped to corresponding characters in  ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/

Question 2

What's the difference between Base64 encoding and decoding?

Accepted Answer

Base64 EncodingThe process of converting binary data to ASCII strings, commonly used for:
            
                Embedding binary data in XML/JSON
                Email attachment encoding
                Image embedding in web pages
            
            Base64 DecodingThe process of restoring encoded strings to original data. Requires:
            
                Valid Base64 string input
                Using the same charset as encoding

Question 3

How much does Base64 encoding increase data size?

Accepted Answer

Since every 3 bytes of binary data becomes 4 ASCII characters, data size typically increases by 33%. Additional characters like line breaks should also be considered in practice.

Question 4

Why use custom charsets?

Accepted Answer

Special scenarios may require compatibility with Base64 variants:1. URL-safe encoding (using -_ instead of +/)2. Filename-safe encoding3. Protocol-specific charset requirements

Base64 Decoder

Tool Introduction

FAQ