Converter Tools

Base64 Decoder

Decode any Base64 string back to its original plain text or binary representation. Inspect JWT token payloads, HTTP Authorization headers, and encoded API responses without any software installation.

Base64 Decoder

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A tool by Digital Checkmark

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How to Use This Tool

Paste the Base64 encoded string into the input box
Click "Decode from Base64" to convert it back to text
Copy the decoded output to inspect or use the original data

What is Base64 Decoder?

Base64 decoding is the reverse of Base64 encoding — it converts a Base64-encoded ASCII string back into the original binary or text data. This is frequently needed when inspecting JWT tokens (the header and payload are Base64url-encoded JSON), debugging HTTP Basic Authentication (the Authorization header contains Base64-encoded credentials), analyzing email attachments (MIME encodes binary attachments as Base64), and examining data URIs embedded in HTML or CSS. Base64url is a variant that replaces + with - and / with _ to make the encoded string safe for use in URLs and filenames without percent-encoding.

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