Free Base64 to XML decoder — decode and check well-formedness

UTF-8-safe Base64, processed entirely in your browser — nothing is uploaded.

Base64 to XML — decode and verify

Decoding Base64 to XML is how you read a document that was packed for transport — most often a SAML response, a SOAP attachment, or an XML field carried inside JSON. This tool decodes UTF-8-safely and checks the result is well-formed XML, all in your browser, so namespaces and the declaration come back exactly as they were.

SAML & the deflate gotcha

The SAML HTTP-POST binding is plain Base64 and decodes directly here. The HTTP-Redirect binding DEFLATE-compresses the XML before Base64, so a redirect SAMLRequest will decode to binary — inflate it first, then it is readable.

If it won't decode cleanly

  • Source used URL-safe Base64 → swap - _ for + /.
  • Output looks like binary → the XML was compressed before encoding.
  • Parser warning → the decoded text simply is not well-formed XML.

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