Base64 Encoder/Decoder
Encode and decode Base64 strings with standard and URL-safe support. All processing happens in your browser — no uploads, no tracking, completely private.
Output will appear here...
About Base64 Encoding
Standard Base64 (RFC 4648 Section 4):
- Uses characters: A-Z, a-z, 0-9, +, /
- Includes = padding
- Suitable for email, data URIs, general encoding
URL-Safe Base64 (RFC 4648 Section 5):
- Uses characters: A-Z, a-z, 0-9, -, _
- No padding characters
- Safe for URLs, filenames, and web applications
Privacy: All encoding and decoding happens locally in your browser using native Web APIs. No data is uploaded to any server.
Keyboard Shortcuts
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100% Private, Instant Processing
All encoding and decoding happens locally in your browser using native Web APIs. Your data never leaves your device, is never uploaded to any server, or transmitted over the internet. Complete privacy guaranteed.
Frequently Asked Questions
What is Base64 encoding?
Base64 is a binary-to-text encoding scheme that converts binary data into ASCII string format. It's widely used for encoding data in emails, data URIs, web tokens (JWT), and anywhere binary data needs to be transmitted as text. Our tool supports both standard Base64 (RFC 4648 Section 4) and URL-safe Base64 (RFC 4648 Section 5).
What's the difference between Standard and URL-Safe Base64?
Standard Base64 (RFC 4648 Section 4):
- Uses characters: A-Z, a-z, 0-9, +, /
- Includes = padding
- Best for general use cases like email attachments and data URIs
URL-Safe Base64 (RFC 4648 Section 5):
- Uses characters: A-Z, a-z, 0-9, -, _
- No padding characters
- Safe for URLs, filenames, and web applications where + and / might cause issues
Does this tool support Unicode characters?
Yes, absolutely! Unlike many online tools, our encoder properly handles full Unicode text including emojis, Chinese characters, Arabic text, and special symbols using modern TextEncoder/TextDecoder APIs. This ensures accurate encoding and decoding of any text.
What's the maximum input size?
The tool supports inputs up to 10MB in size. For larger inputs, we automatically debounce the encoding/decoding operations to maintain smooth performance. The tool also displays the current input size to help you stay within limits.
Is my data safe? Does it get uploaded anywhere?
Yes, your data is completely safe. All encoding and decoding happens locally in your browser using native JavaScript APIs (TextEncoder, TextDecoder, btoa, atob). No data is ever sent to our servers or any third party. You can even disconnect from the internet after loading the page and the tool will continue to work perfectly.
What are common use cases for Base64?
Base64 is commonly used for:
- Embedding images in HTML/CSS (data URIs)
- JWT tokens for authentication
- Email attachments (MIME encoding)
- URL parameters and cookies
- API request/response data
- Storing binary data in text-based formats like JSON or XML