To keep a human-readable record of what was actually sent versus what is in your accounting software.
You can import SII XML files directly into Excel, which handles the "decryption" and flattening of data automatically. sii decrypt online
Your SII files contain sensitive business information, including: Tax Identification Numbers (NIF/CIF). Client and provider names. Total invoice amounts and bank details. To keep a human-readable record of what was
Open your file in a text editor (like Notepad). If you see a long string of random characters (e.g., PHhtbCB2ZXJzaW9u... ), it is . If you see a giant wall of text starting with , it is simply unformatted . 2. Use a Trusted Decoder To decode Base64 SII data: Copy the encoded string. Use a reputable Base64 to XML converter . Paste the code and hit "Decode." 3. Use an XML Formatter Client and provider names