Base64 Encoder & Decoder Online

About the Base64

This free online Base64 encoder and decoder converts text to Base64 and back instantly in your browser. Developers use it to embed images in CSS, encode API credentials, and package data into JSON - private, with nothing uploaded, since every conversion runs client-side.

Base64 is an encoding scheme that represents binary data using 64 ASCII characters, making it safe to transmit through systems that only handle text — email attachments, JSON payloads, data URIs, and HTTP headers. Developers reach for Base64 constantly: embedding images in CSS, encoding API credentials, or packaging binary files into JSON.

This encoder and decoder runs entirely in your browser. Nothing you paste is ever uploaded, logged, or stored — important when you are encoding API keys, tokens, or customer data. It fully supports UTF-8, so emojis and non-Latin text encode and decode correctly.

Use cases and examples

Embed small images directly in stylesheets as data URIs to avoid extra HTTP requests. Encode the binary, then reference it: url(data:image/png;base64,<encoded>).

Debug HTTP Basic authentication: the Authorization header is just Base64 of user:password - decode one to verify what a client sends, or build one to test a server.

Prepare payloads for JWT work: the header and payload segments of a JWT are Base64URL-encoded JSON. Decoding them here is the first step of inspecting any token.

Authorization: Basic dXNlcjpwYXNzd29yZA==  // base64("user:password")

How to use

1. Paste or type your text into the input field on the left.
2. The Base64-encoded result appears instantly in the output panel.
3. To decode, paste Base64 into the input and switch to decode mode.
4. Click Copy to copy the result to your clipboard.

Frequently Asked Questions