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 — Free Online Tool

Decode Base64 to XML online, free. Base64 to XML decoding reverses Base64 (RFC 4648) back to text and checks the result is well-formed XML — the quick way to read a SAML SSO response or any Base64-wrapped XML payload. Decoding runs entirely in your browser, so SAML responses and documents stay private.

🚀 Why use this Base64 to XML tool?

It decodes UTF-8-safely and verifies well-formedness, and flags when the input was URL-safe or compressed (e.g. a deflated SAML redirect) rather than plain Base64. 100% free, no registration, and complete privacy — everything runs locally in your browser, so your data never touches a server.

Key Features

🔓Decode & check

Decodes the Base64 and confirms the result is well-formed XML, with the parser's reason if not.

🔐SAML-friendly

Read a Base64-encoded SAMLResponse assertion (HTTP-POST binding) directly.

📐Byte-exact

Restores the declaration, namespaces and attributes exactly as encoded.

🔒100% private

SAML responses and payloads never leave your device.

Popular Use Cases

SSO & enterprise

  • Decode a SAMLResponse
  • Inspect a SOAP blob
  • Read an encoded assertion

Debugging

  • Unwrap a Base64 XML field
  • Verify what was encoded
  • Check transport payloads

Dev

  • Recover a stored XML value
  • Sanity-check encoding
  • Read a data: URI

What It Handles

Decodes

  • Base64 → XML
  • UTF-8 safe
  • Well-formedness check

Handles

  • Standard Base64
  • Raw fallback
  • Error reason

Privacy

  • Client-side only
  • No network calls
  • Runs offline

Sources & References

Frequently Asked Questions

How do I decode Base64 to XML?

Paste the Base64 string and click Decode. The tool decodes the bytes back to text and checks the result is well-formed XML. If it is not, the raw decoded text is still shown with the parser's reason.

How do I decode a SAML response?

A SAML SSO SAMLResponse is Base64-encoded XML — paste it here to read the assertion. Note that some bindings additionally deflate the XML before Base64 (HTTP-Redirect binding); if the decode looks like binary, it was deflated and needs inflating first. The HTTP-POST binding is plain Base64 and decodes directly.

Why is my decoded XML unreadable?

Two common causes: the source used URL-safe Base64 (- and _ instead of + and /), or the XML was compressed before encoding. The tool reports when the decoded text is not well-formed XML so you can distinguish a bad alphabet from compressed input.

Does decoding keep namespaces and the declaration intact?

Yes. Base64 is byte-exact, so the <?xml?> declaration, namespaces and attributes are restored exactly as they were before encoding. The decoder is UTF-8-safe for non-ASCII content.

Is my data sent anywhere?

No. Decoding and well-formedness checking run entirely in your browser. SAML responses and payloads never leave your device.

🎓 Pro Tips

  • Tip 1: SAML HTTP-POST is plain Base64 (decodes here directly); HTTP-Redirect is deflated first and needs inflating.
  • Tip 2: If the decode looks like binary, the source was compressed before Base64 — that's expected for redirect-binding SAML.
  • Tip 3: URL-safe Base64 (- and _) must be converted to + and / before decoding.