Base64 Encoder / Decoder
Convert text to and from Base64 (UTF-8 safe). Runs entirely in your browser.
How to encode or decode Base64
- Choose a mode. Select "Encode" or "Decode."
- Enter your input. Type or paste your text or Base64 string.
- Run it. Click "Run," use "Swap" to flip direction, or copy the output.
What happens to your text
Encoding and decoding both happen using your browser's built-in Base64 and UTF-8 APIs, running entirely in the current tab. Nothing you type is sent to OpenToolkit.
What this tool supports
ModesEncode or decode
EncodingUTF-8 safe — handles emoji and non-ASCII text
InputTyped or pasted text
OutputSwap direction instantly, or copy the result
ProcessingEntirely in your browser tab
Common reasons to use this tool
- Decode a Base64 payload found in an API response or a JWT.
- Prepare a Basic Auth header value for testing an API.
- Check what a Base64-encoded string actually contains while debugging.
- Encode a short string for embedding somewhere that expects Base64 text.
Frequently asked questions
Is my text uploaded anywhere?
No. Encoding and decoding happen entirely in your browser tab.
Does it handle emoji and non-English text?
Yes — encoding is UTF-8 safe, so emoji and non-ASCII characters round-trip correctly.
Can it encode or decode files, not just text?
Not currently — this tool works on typed or pasted text only.
What if decoding fails?
An error is shown if the input isn't valid Base64 — double-check you copied the complete string without extra whitespace or line breaks.
Is Swap the same as running it again?
Swap flips the mode and moves your last output into the input box, so you can immediately reverse the conversion.
Last reviewed: August 2026