Dev Brains AI
AIDevTools

Base64 Encoder / Decoder

Encode plain text to Base64 or decode Base64 back to text — entirely in your browser. Your data is never uploaded.

Base64 output

What is Base64?

Base64 is a binary-to-text encoding scheme that represents binary data as an ASCII string using 64 printable characters (A–Z, a–z, 0–9, +, /). It is widely used when binary data needs to be stored or transmitted over media designed to handle text.

Common use cases for Base64

  • Embedding images in HTML/CSS as data: URIs
  • Encoding file attachments in email (MIME)
  • Encoding the payload portion of a JWT token
  • Passing binary data in JSON API fields
  • Storing small assets in environment variables or config files
  • HTTP Basic Authentication (username:password → Base64)

Standard vs URL-safe Base64

Standard Base64 uses + and /, which have special meanings in URLs. URL-safe Base64 replaces these with - and _ respectively and omits the padding = characters. Use URL-safe mode when embedding Base64 in URLs, filenames, or JWT tokens.

Tips & best practices

  • Base64 encoding increases data size by ~33% — avoid for large files in APIs.
  • Base64 is encoding, not encryption — never use it to "hide" sensitive data.
  • For multi-byte text (e.g. Unicode, Emojis), use UTF-8 encoding before Base64.
  • This tool correctly handles UTF-8 text so emojis and accented characters work.

FAQ: Base64 Encoder / Decoder

Is this Base64 tool free?
Yes — the Base64 encoder and decoder on Dev Brains AI is completely free to use with no signup required.
Does my data get uploaded to a server?
No. All encoding and decoding runs entirely in your browser using the built-in JavaScript atob/btoa functions. Your data never leaves your device.
What is Base64 used for?
Base64 is used to encode binary data (images, files) as text for safe transmission in emails, JSON payloads, data URIs, HTTP headers, and JWTs.
Can I encode images or files?
This tool encodes and decodes text strings. For file-to-Base64 conversion, use the file picker which reads the file and encodes its binary contents.
What is URL-safe Base64?
URL-safe Base64 replaces + with - and / with _ so the result can be used directly in URLs and filenames without percent-encoding.

More developer tools from Dev Brains AI

Try our URL Encoder / Decoder for percent-encoding, our JSON Formatter for pretty-printing JSON, or the AI Regex Generator to build regex patterns from plain English.