Base64 Encoder / Decoder

The Base64 Encoder / Decoder is a small, focused utility for converting between raw text and Base64 (and Base64URL) strings. It handles UTF-8 text, padding, and URL-safe variants, and is designed to be copy-paste friendly for everyday debugging and integration work.

• Paste or type the original value (e.g. JSON, tokens, IDs) into the input area.
• Choose whether you're working with Base64 or Base64URL (URL-safe).
• Use the Encode / Decode actions to convert between raw text and Base64.
• Copy the result directly into your code, config, headers, or test payloads.

The tool assumes UTF-8 text for the "raw" side. If you are working with binary data (files, images, etc.), make sure the producing or consuming system treats the data as raw bytes and not as text. When in doubt:

• For API headers and tokens, text mode is usually correct (Authorization, Basic auth, etc.).
• For file uploads or binary blobs, confirm how the other side encodes/decodes bytes.

Many systems use a URL-safe variant of Base64 where + and / are replaced with - and _, and padding = is optional. The tool helps you:

• Normalize a Base64URL string back to standard Base64 for use with libraries that don't support URL-safe encoding.
• Convert standard Base64 into Base64URL when you need to use it in query parameters or path segments.

Standard Base64 output is padded with one or two = characters to reach a length that's a multiple of four. Some systems:

• Require padding and treat missing padding as an error.
• Omit padding (especially Base64URL) and accept both padded and unpadded input.

The tool can read both forms, and when encoding, it follows a consistent, predictable strategy so you always know what to expect.

All encoding and decoding is done with UTF-8 under the hood. This means characters like Chinese text, emoji, and other multi-byte symbols are handled correctly:

• No mojibake when copy-pasting between tools.
• Base64 output matches what you'd get from standard UTF-8 capable libraries.

When the input is not valid Base64 (invalid characters, wrong length, impossible padding), the tool surfaces a clear error instead of silently producing incorrect output. Treat this as a hint to check:

• Whether the data is actually Base64 or some other encoding.
• Whether you need to switch between Base64 and Base64URL modes.
• Whether part of the value was truncated or escaped.

The tool uses browser-native primitives for Base64 operations where possible, falling back to a small, well-tested implementation when needed. The core pipeline looks like:

• Convert text input to a UTF-8 byte array (or decode Base64 into bytes).
• Run bytes through Base64 or Base64URL logic.
• Render the result back as text in the opposite panel.

No backend or external service is involved; all operations happen entirely in your browser.

Base64 often wraps sensitive data (tokens, credentials, internal IDs). Birdor's Base64 tool is designed with that in mind:

• All processing is done client-side.
• No analytics events based on your input.
• No caching of encoded/decoded text between sessions.

For large payloads, the tool avoids unnecessary copies and keeps operations streaming where possible so it stays responsive even with big blobs of data.

• JSON Formatter & Viewer — often used together when debugging APIs that embed JSON in Base64.
• JWT Debugger — JWTs are Base64URL-encoded; this tool builds on the same decoding principles.

If you're unsure which tool to start with, the JSON Formatter and JWT Debugger are good companions to the Base64 tool for most backend and auth debugging tasks.