Question 1

What is Base64 encoding used for?

Accepted Answer

Base64 converts binary data into a text-safe alphabet of 64 characters (A-Z, a-z, 0-9, + and /) so it can travel through text-only channels such as JSON, XML, data URIs, email (MIME), and HTTP headers without corruption.

Question 2

What is the difference between standard and URL-safe Base64?

Accepted Answer

Standard Base64 uses + and / characters, which have special meanings in URLs. URL-safe Base64 replaces them with - and _ respectively. Decoding here accepts both variants automatically.

Question 3

Why do some Base64 strings end with = signs?

Accepted Answer

Base64 encodes data in 3-byte groups that produce 4 output characters. When the input length is not divisible by 3, = characters are appended as padding. Padding is optional when decoding.

Question 4

Is Base64 encryption?

Accepted Answer

No. Base64 is a reversible encoding, not encryption — anyone can decode it instantly. Never use it to protect passwords or secrets; use proper encryption or hashing instead.

Character	Encoded	Common context
space	%20	query strings & paths
+	%2B	literal plus in values (a bare + means space in forms)
&	%26	parameter separators
=	%3D	key=value delimiter
#	%23	fragment start
é	%C3%A9	UTF-8 two-byte sequence

Base64 & URL Encoder / Decoder

How Base64 Works (and When to Use It)

Data URIs

APIs & JWTs

Email (MIME)

URL Encoding: Which Characters Get Escaped?

Frequently Asked Questions