Base64 Decoder

Decode Base64 when you need the readable value behind an encoded payload

Base64 is a transport format, not a readable end state. When you need to inspect the actual text behind a token, response body or attachment snippet, this decoder converts it locally in your browser and shows a clear error if the input is invalid. That makes it useful for quick checks without sending anything off the machine.

What to keep in mind

Decoding works best when the input is truly Base64 and the padding, line breaks and spacing are correct. If the result looks wrong, the issue is often the source format rather than the decoder itself. Base64 is commonly used for JWTs, API responses, email attachments, data URIs and other encoded payloads, so this tool is a good first stop when you need to verify what a string actually contains.

Practical workflow

A good habit is to paste the encoded value, confirm that the decoded output looks sensible, and then check whether the source system expected the same alphabet and padding rules. If you are comparing variants, like URL-safe Base64 versus standard Base64, the differences become obvious very quickly. For developer work, that saves time and makes encoded data much easier to reason about.