Base64 Encoder & Decoder
100% Client-Side • Local Browser Processing100% Client-Side Processing
All encoding and decoding uses native btoa/atob and TextEncoder/TextDecoder APIs. Your data never leaves your browser.
URL-Safe Base64 (RFC 4648)
Toggle URL-safe mode to replace + with -, / with _, and strip padding. Safe for use in URLs and HTTP headers.
File to Data URI
Upload any file to instantly generate a Base64-encoded Data URI, ready for embedding in HTML, CSS, or API payloads.
How Base64 Encoding Works
Base64 encoding translates binary data into a set of 64 ASCII characters. Here is how the process works in your browser:
- Input Parsing: Plaintext or uploaded files are read into an ArrayBuffer or UTF-8 byte stream using TextEncoder.
- Bit Chunking: Data bytes are grouped into 24-bit blocks and divided into four 6-bit index numbers.
- Character Lookup: Each 6-bit index maps directly to a character in the RFC 4648 Base64 alphabet.
- Padding & Output: Trailing '=' characters are appended as necessary to align 24-bit boundaries.
Client-Side Base64 Security
Encoding sensitive credentials or certificates with cloud utilities risks data leakage. Local processing ensures full safety:
Zero Server Transmission: TextEncoder and Web APIs handle all conversions locally on your machine.
URL-Safe Standard Support: Encode tokens for web headers safely without exposing payload values to remote proxies.
Frequently Asked Questions
Built for Daily Developer Workflows
Free, browser-based utilities that format, validate, and convert data locally. No accounts, no ads, no backend data collection.