Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 strings with real-time conversion and full Unicode support
Introduction
Need to encode authentication credentials for API headers, embed images in HTML as data URLs, or decode Base64 strings to see their original content? Our Base64 Encoder/Decoder handles bidirectional conversion with real-time processing and full Unicode support. Encode plain text into Base64 format for transmission over text-based protocols, or decode Base64 strings back to readable text. Perfect for developers working with APIs, email attachments, data URLs, or any system requiring text-safe binary data encoding. Switch between encode and decode modes instantly, and the tool automatically handles emojis, international characters, and all Unicode text. Everything processes in your browser with no server uploads, ensuring complete privacy for sensitive data like credentials and tokens.
Who Should Use This Tool?
- Backend developers encoding credentials for HTTP Basic Authentication headers in API requests
- Frontend engineers embedding images as data URLs to reduce HTTP requests in single-page applications
- Email developers working with MIME-encoded attachments in HTML email templates
- DevOps engineers storing binary tokens and certificates in text-based configuration files
- API developers testing and debugging Base64-encoded request and response payloads
- Security professionals inspecting JWT token components during authentication troubleshooting
- Data engineers encoding binary data for safe transmission through text-only protocols
- Full-stack developers working with Base64-encoded resources in JSON APIs and data structures
- Web developers creating self-contained HTML documents with embedded assets
- System administrators managing Base64-encoded secrets in environment variables
How This Tool Works
Base64 encoding converts binary data into ASCII text format by representing every 3 bytes of input using 4 ASCII characters from a 64-character alphabet (A-Z, a-z, 0-9, +, /). This transformation makes binary data safe for transmission through systems designed only for text, such as email protocols, JSON files, or URL parameters. The encoding process groups input bytes into 6-bit chunks, then maps each chunk to one of 64 printable ASCII characters. When input length isn't divisible by 3, padding characters (=) fill the output to maintain proper alignment. Our tool performs this conversion instantly in your browser using modern JavaScript APIs, automatically handling Unicode text through UTF-8 encoding before Base64 transformation. For decoding, the process reverses: Base64 characters map back to 6-bit values, which recombine into original 8-bit bytes. The tool validates input during decoding, detecting invalid characters or corrupted strings, and provides immediate error feedback. Real-time conversion means results appear as you type, with no button clicks or processing delays. The 'Switch & Swap' feature lets you test roundtrip conversion—encode text to Base64, then immediately decode it back to verify accuracy without copying and pasting. All processing happens client-side using the browser's native TextEncoder and btoa/atob functions, ensuring your data never leaves your device and conversion is instantaneous regardless of input size.
Try Base64 Encoder/Decoder Now
Use the interactive tool below to get instant results
Client-Side Processing
All encoding and decoding happens in your browser. No data is sent to any server. Full Unicode support included.
Conversion Mode
Plain Text Input
💡 Quick Tips
- • Real-Time: Conversion happens automatically as you type
- • Unicode Support: Handles emojis, special characters, and international text
- • Switch & Swap: Quickly reverse the conversion with one click
- • Copy Output: Click the copy button to copy results to clipboard
- • Validation: Decoder validates Base64 format before processing
📖 What is Base64?
Base64 is an encoding scheme that converts binary data into ASCII text format using 64 characters (A-Z, a-z, 0-9, +, /). It's commonly used to encode data for transmission over text-based protocols.
Common uses: Email attachments, data URLs, API authentication tokens, embedding images in HTML/CSS.
ℹ️ Base64 Format
- • Uses characters: A-Z, a-z, 0-9, +, / (64 characters total)
- • Padding character: = (added to make length multiple of 4)
- • Output is ~33% larger than original data
- • Whitespace is ignored during decoding
- • Invalid characters will cause decoding errors
How to Use Base64 Encoder/Decoder
Select Conversion Mode
Choose "Encode" to convert plain text into Base64 format, or select "Decode" to convert Base64 strings back to readable text. You can switch modes anytime using the mode selector, and the tool remembers your preference for your next visit.
Enter Your Input
Type or paste your text (when encoding) or Base64 string (when decoding) into the input area. Conversion happens automatically in real-time as you type - no need to click buttons or wait for processing. The tool handles any length input and provides instant feedback.
View the Result
The converted output appears immediately below your input with character and byte counts for both input and output. For encoding, you'll see valid Base64 output. For decoding, invalid Base64 input triggers error messages pointing to the problem so you can fix it.
Copy or Switch
Click "Copy" to place the result on your clipboard, ready to paste anywhere. Use "Switch & Swap" to reverse the conversion mode and use the current output as new input - perfect for testing whether your Base64 encodes and decodes correctly without retyping.
Use Cases for Base64 Encoder/Decoder
API Authentication Headers
Encode username and password combinations for HTTP Basic Authentication headers. Many REST APIs require credentials in the format "Basic base64(username:password)". The tool handles the encoding instantly, making it easy to test API endpoints with authentication requirements.
Data URLs and Embedded Resources
Encode small images, icons, or files as Base64 for embedding directly in HTML, CSS, or JSON without external file references. Data URLs (data:image/png;base64,...) eliminate extra HTTP requests, useful for email templates or single-file HTML documents.
Email Attachments and MIME Encoding
Encode binary files for transmission in email systems that only support text. MIME (Multipurpose Internet Mail Extensions) uses Base64 to safely transmit attachments through email protocols that can corrupt binary data, ensuring files arrive intact.
Configuration and Data Storage
Store binary data like tokens, certificates, or encrypted values in text-based configuration files, environment variables, or databases that only accept string types. Base64 encoding makes binary data safe for JSON files and command-line arguments.
JWT Token Inspection
Decode Base64-encoded JWT token components to inspect headers and payloads. While JWTs use URL-safe Base64 variants, this tool helps you understand token contents during development and debugging, revealing claims and metadata without requiring specialized JWT tools.
Key Features
100% Private and Instant
All Base64 encoding and decoding happens entirely in your browser using JavaScript. Your text never leaves your device, nothing is uploaded to any server, and processing is instantaneous with zero delays - perfect for sensitive credentials or confidential data.
Real-Time Conversion
Output updates automatically as you type or paste, with no buttons to click or processing waits. See immediate feedback on every change, helping you verify encoding correctness or spot decoding errors without manually triggering conversions.
Full Unicode Support
Properly handles all Unicode characters including emojis, Chinese/Japanese/Korean text, Arabic, Cyrillic, and special symbols using UTF-8 encoding. The tool automatically manages the complexity of multi-byte characters, ensuring accurate encoding and decoding without data corruption.
Invalid Input Detection
When decoding, the tool immediately identifies invalid Base64 strings and displays clear error messages. Know instantly if your Base64 is corrupted, incomplete, or contains invalid characters, saving debugging time and preventing cryptic errors.
Switch and Swap Functionality
One-click switching between encode and decode modes with automatic input/output swapping. Test whether your encoded data decodes correctly without copying and pasting, or verify that decoded data matches the original by re-encoding immediately.
No Software or Registration
Works instantly in any modern web browser without downloads, installations, or account creation. Access the tool anytime from any device - no setup required, no personal information collected.
Frequently Asked Questions
Does this tool upload my data to a server?
No, absolutely not. All Base64 encoding and decoding happens entirely in your web browser using JavaScript. Your text never leaves your device, nothing is uploaded anywhere, and no one except you can see your data. This makes the tool completely safe for encoding credentials, tokens, or any sensitive information.
Is Base64 encoding a form of encryption?
No! Base64 is an encoding method, not encryption. Anyone can decode Base64 strings instantly - it provides zero security. Base64 makes data unreadable at a glance but offers no protection. For sensitive data, use proper encryption (like AES) before Base64 encoding for transmission.
Why is my Base64 decoding failing with an error?
Base64 decoding fails if the input contains characters outside the valid Base64 alphabet (A-Z, a-z, 0-9, +, /, =) or if the string is corrupted or incomplete. Ensure you copied the entire Base64 string including padding (= characters). Whitespace and line breaks are automatically ignored, so those won't cause errors.
Why is my Base64 output longer than the original text?
Base64 encoding increases data size by approximately 33% because it represents every 3 bytes using 4 ASCII characters. This overhead is the necessary tradeoff for converting binary data into text-safe format that can pass through text-based systems without corruption or data loss.
Can this tool handle emojis and special characters?
Yes! This tool uses UTF-8 encoding with modern JavaScript TextEncoder/TextDecoder APIs, which properly handle all Unicode characters including emojis (😀), Chinese/Japanese characters (中文/日本語), Arabic (العربية), and special symbols. Just paste your text - the tool handles the encoding complexity automatically.