Base64 Encoder / Decoder — Encode & Decode Text Safely in the Browser
Base64 encoding turns binary data or text into a string of ASCII characters that can be safely used in URLs, JSON, or email. Decoding reverses the process. You might need it for API tokens, data URLs, or config values that are stored as Base64. Doing this in the browser with a dedicated tool is faster than writing one-off scripts, and you keep full control: nothing is sent to a server. This encoder and decoder supports UTF-8, so you can encode and decode Unicode text correctly in both directions. Whether you're inspecting a token, building a small payload, or teaching how encoding works, having a reliable client-side tool makes the job straightforward. Base64 is not encryption—anyone with the string can decode it—so use it for encoding only. For credentials or secrets, combine encoding with proper transport and storage security. This tool focuses on correctness and speed so you can round-trip text and binary data without leaving your tab.
What Does This Tool Do?
This tool encodes plain text to Base64 and decodes Base64 strings back to text. In the input area you either type or paste the text you want to encode, or the Base64 string you want to decode. Click Encode to convert the input to Base64 using the same rules as JavaScript's btoa on UTF-8 bytes (via TextEncoder), so Unicode characters are handled correctly. Click Decode to turn a Base64 string back into text; the tool uses atob and TextDecoder so the output is correct for UTF-8. If the decode input is invalid Base64, you get a clear error message. Whitespace in the Base64 input is ignored when decoding. All processing runs in your browser; no data is sent to any server. You can copy the result or clear the fields and start over. The implementation follows the standard Base64 alphabet (A–Z, a–z, 0–9, +, /) with = padding when needed, so the output is compatible with other systems and libraries. For Base64URL (which uses - and _), you would need to substitute those characters before or after using this tool.
How to Use It (Step-by-step)
Paste or type into the Input area. For encoding, enter the plain text (any language or symbols). For decoding, enter the Base64 string; you can include line breaks or spaces, they will be stripped before decoding.
Click Encode to convert text to Base64, or Decode to convert Base64 to text.
Check the Output area. If decoding failed, an error message appears and you can correct the input (ensure it only uses valid Base64 characters: A–Z, a–z, 0–9, +, /, and optional = padding).
Use Copy to copy the output to the clipboard.
Use Clear to reset input and output when finished. For best results, use Decode only on strings that were produced by a proper Base64 encoder.
Key Features & Use Cases
- Client-side only: no data is sent to a server.
- UTF-8 encode and decode so Unicode text round-trips correctly.
- Encode: convert any text to Base64 in one click.
- Decode: convert Base64 back to text with clear errors for invalid input.
- Copy the result to the clipboard.
- Encode credentials or tokens for use in headers or config.
- Decode a JWT payload (without verification) to inspect claims.
- Encode small binary or text data for embedding in JSON.
- Inspect Base64 strings from API responses or logs.
- Build or decode data URLs (e.g. inline images).