100% client-side · Zero data transmission

Decode Base64 Safely with AI
Privacy-First Security Decoder

100% client-side. Your JWTs and API tokens never leave your browser. With AI security audit that explains what's inside in plain English.

Decode & Audit →Free · No account · Nothing leaves your browser
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100% Client-Side
All decoding happens in your browser. Zero server calls for decode/encode.
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AI on Decoded Text Only
The AI audit analyses only the decoded string — never your raw token or key.
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No Logging
We don't log your input, output, or IP address. GDPR-friendly by design.

Try It: Paste a JWT and See the Audit

JWT detected · Risk: Medium
Input (Base64-encoded JWT)
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwiZW1haWwiOiJhbGljZUBleGFtcGxlLmNvbSIsInJvbGUiOiJhZG1pbiIsImlhdCI6MTcwMDAwMDAwMCwiZXhwIjoxNzAwMDg2NDAwfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
JWT Header
{
  "alg": "HS256",
  "typ": "JWT"
}
JWT Payload
{
  "sub": "1234567890",
  "email": "alice@example.com",
  "role": "admin",
  "exp": 1700086400
}

🛡️ AI Security Audit — Risk: Medium

This JWT contains an email address and admin role. Signature is NOT verified client-side. Token expires 2023-11-15. Treat with care if sharing.

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All Edge Cases Handled

Real-world Base64 is messy. We handle all of it.

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Standard Base64
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URL-Safe Base64
Auto-converts - and _ back to + and /
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Broken Padding
Auto-pads missing = characters
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Auto-Detect
Identifies encoding variant and content type
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JWT Analysis
Decodes header + payload, shows claims clearly
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File Encoding
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