🔤 Base64 Decoder
Paste a Base64 string and read what is inside – text, JSON or a downloadable file.
🔒 Runs in your browser · files never uploaded
Drop a file here or click to browse Any file → Base64 (with a ready-to-use data: URI). Files stay on your device.
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How to use the Base64 Decoder tool
- Paste the Base64 (with or without padding, data: prefix allowed).
- Read the decoded text in the output box.
- If it is binary, click Download to save the raw bytes.
Frequently asked questions
Why do I get "not valid Base64"?
Base64 only uses A–Z, a–z, 0–9, + and / (or - and _ for URL-safe). Stray characters such as quotes, %3D from URL encoding, or a truncated copy will fail. Spaces and line breaks are ignored.
The output says binary – what does that mean?
The bytes are not valid UTF-8 text, so it is probably an image, PDF or compressed data. Use Download to save it, then open it with the right app.
Can I decode a JWT with this?
Each JWT segment is Base64URL, so yes – but the JWT Decoder splits the parts, pretty-prints the JSON and shows the expiry for you.