Base64 decoder
What this Base64 decoder does
Paste a Base64 payload and recover the original byte sequence interpreted as text when possible. Strip PEM banners (-----BEGIN...) if your paste came from a certificate block—only the middle alphabet belongs here. If decoding yields gibberish, you may be looking at gzip-wrapped content, a UTF-16 string, or the wrong URL-safe alphabet variant.
When to use it
Use it to inspect opaque tokens during API debugging, compare two environments' claims blobs, or verify that a mobile client Base64s JSON exactly the way the backend expects. Pair with Base64 encoder for symmetry checks, and treat decoded binaries from untrusted sources as potentially malicious—preview images through Base64 to Image instead of executing unknown files.
Worked example
Support sends a failing SAML assertion chunk. You isolate the inner Base64 layer, decode it here, and confirm whether the XML references the staging issuer URL—proving config drift rather than a crypto regression.
Frequently asked questions
Why "invalid input" with copied certs?
Headers, footers, or missing newlines may introduce illegal symbols. Remove armor lines and whitespace-only gaps.
Is decoding safe?
Decoding itself just reverses encoding. Risk comes from what you do next—never run unknown binaries.
Why mojibake after decode?
The source might be Latin-1, UTF-16, or compressed. Confirm charset assumptions with your protocol spec.