What if I paste invalid Base64?

The tool validates the input first and shows a clear error message (for example about bad characters or padding) instead of producing garbled output.

Is my data uploaded anywhere?

No. Encoding and decoding happen entirely in your browser. Nothing is sent to a server, which makes it safe for tokens, API keys, and other sensitive values.

What are the byte sizes shown for?

They show the input size in bytes and the output size in bytes. Base64 output is roughly 33% larger than the input, so this helps you verify payload sizes for headers, URLs, and data URIs.

Base64 Encoder & Decoder

Encode and decode Base64 with full Unicode support

Text to encode0 bytes

Base64 output0 bytes

Unicode-safe: text is converted to UTF-8 bytes before encoding, so emoji and non-English characters round-trip correctly. Everything runs in your browser, nothing is sent or stored anywhere.

About this tool

Base64 encoding is everywhere in modern development: embedding images in data URIs, passing tokens in HTTP headers, storing binary data in JSON, and building auth credentials. But many online tools mishandle Unicode, pasting text with emoji or non-English characters into a naive encoder silently corrupts it. JoliTools' Base64 encoder is Unicode-safe by design: text is converted to UTF-8 bytes first, so every character round-trips perfectly.

The tool covers both directions in one clean interface. The Encode tab turns any text into Base64; the Decode tab turns Base64 back into readable text, with strict validation that catches malformed input and explains what is wrong. Live input and output byte sizes help you keep track of payload growth, which matters when you are sizing JWTs, data URIs, or API payloads.

How to use the base64 encoder & decoder

1Choose the Encode tab to convert text to Base64, or Decode to convert Base64 back to text.
2Type or paste your input into the top textarea.
3The result appears instantly in the output box, with input and output byte sizes.
4Use “Copy output” to copy the result, or “Clear” to reset.
5The swap button converts the current output and switches tabs, so you can round-trip in one click.

Good to know

Privacy is the point. Base64 is often used with API keys, session tokens, and auth credentials, exactly the data you should never paste into a server-side tool. This encoder and decoder run 100% in your browser with no network calls, so your values never leave your device. There is nothing to install and no account required.

Frequently asked questions

Yes. Text is converted to UTF-8 bytes before encoding, so emoji, accented characters, and non-Latin scripts encode and decode correctly, unlike naive btoa-based tools that corrupt them.

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