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Base64 Lab

Local codec

Base64 Lab

Encode, decode, normalize, and inspect common Base64 alphabet variants without posting input back to WordPress.

Client-side No upload
Default modeAuto detect
AlphabetsStandard Base64, Base64URL, IMAP modified Base64, bcrypt radix-64, crypt radix-64, and Custom alphabet
PaddingKept by default
InspectionByte counts visible

Input

Output

Input bytes0
Output bytes0
OperationReady

No data leaves this page.

Use Encoding Wisely

Quick notes for reading Base64 output correctly without treating it as protection.

What Base64 does

Base64 changes bytes into text that is easier to move through forms, URLs, APIs, and configuration files.

What Base64 does not do

Base64 is not encryption. Anyone can decode it, so do not use it to hide passwords, tokens, or private data.

Why alphabets differ

Some systems swap the last two Base64 characters or use a different 64-character order. Match the alphabet to the system that produced the value.

Which alphabet fits
  • Standard Base64: general RFC 4648 text encoding.
  • Base64URL: URLs, JWTs, and web APIs.
  • IMAP modified: mail server and mailbox formats.
  • bcrypt and crypt radix-64: existing hash formats only. They do not make passwords safer by themselves.
Custom alphabets

A custom alphabet is for testing formats. It must contain exactly 64 unique characters, and both sides must use the same alphabet to decode correctly.

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