🔓
Base64 Decoder
Decode Base64 encoded strings back into clean, readable text. Full UTF-8 and multilingual character support with instant error detection for corrupted payloads.
Decoded text will appear here as you type...
What is Base64 Decoder?
Base64 Decoder is an online utility that converts RFC 4648 Base64 ASCII strings back into their original plain text or binary representation.
How Base64 Decoder Works
The decoder maps 4-character Base64 blocks back into 3 original 8-bit bytes, removing padding characters and reconstructing the original byte sequence via `TextDecoder('utf-8')`.
Key Features
- ✓Full UTF-8 decoding support for international characters and emojis
- ✓Identifies invalid characters and malformed padding lengths
- ✓One-click copy of decoded text
Common Use Cases
- •Inspecting Basic Auth HTTP request headers during API debugging
- •Decoding Base64 data chunks from email MIME attachments and webhook payloads
- •Analyzing obfuscated strings in configuration files and scripts
Examples & Sample Data
Decoding Base64 String
Input
SGVsbG8sIFdvcmxkIQ==Output
Hello, World!Reconstructs the original ASCII/UTF-8 string from Base64.
🔒
100% Client-Side Privacy Guarantee
Decoding runs 100% locally in your web browser. No token or secret is ever sent to our servers.
How to Use Base64 Decoder
- 1
Paste your Base64 string into the input box.
- 2
Click 'Decode Base64'.
- 3
Copy the decoded plain text.