Base64 Encoder & Decoder
Convert any text to Base64 or decode Base64 back to readable text. Encoding and decoding happens instantly as you type — no server, no tracking.
Invalid Base64 string
Encoding in progress…
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About this tool
The Base64 Encoder & Decoder is a dual-purpose utility for converting between plain text and Base64-encoded strings entirely in your browser. Base64 encoding represents binary data in an ASCII string format using a 64-character radix, making it safe to transmit over text-based protocols that expect only printable characters.
Front-end and back-end developers frequently use Base64 to embed images directly in CSS or HTML as data URIs, eliminating extra HTTP requests and reducing page load latency. API developers rely on it for encoding authentication tokens and credentials in HTTP Authorization headers, particularly with Basic Auth or when passing binary payloads inside JSON structures. Email systems use Base64 to encode file attachments in MIME messages, ensuring binary files like PDFs and images travel safely over SMTP. Data engineers migrating structured data may encode entire JSON objects as Base64 strings to nest them inside other JSON payloads without worrying about escaping special characters.
This tool performs all encoding and decoding in real time as you type — there is no submit button to click. If you try to decode an invalid Base64 string, a clear error message explains what went wrong. The Swap button instantly flips input and output, making round-trip conversions effortless. Since every operation runs on your device using JavaScript's native btoa and atob functions with full Unicode support, no data is ever uploaded, logged, or shared with any server — matching CollateKit's commitment to 100% browser-based, privacy-first tooling.