Base64 Decoder

Base64 Decode converts Base64‑encoded strings back into plain text. Paste any Base64 payload and the tool will decode it instantly, showing a clear result or an error if the input is not valid.

This is useful when inspecting data from HTTP headers, data URIs, tokens, or exports that are commonly encoded for safe transport. The decoder handles typical padding and whitespace gracefully.

Key features

• Fast, in‑browser Base64 decoding
• Two‑panel layout with toolbar actions (Copy, Clear, Sample)
• Helpful error messages for invalid characters or padding
• Local persistence that restores your last input
• Keyboard accessible UI and ARIA‑labeled controls

Common use cases

• Decoding text embedded in data URIs
• Reading Base64 fields from API responses or logs
• Checking small payloads before converting them to JSON with JSON Viewer

Privacy & security: decoding happens entirely in your browser; nothing is uploaded. Do not paste secrets or large binary blobs you do not trust.

1. Focus the left input and paste your Base64 string.
2. If the input is valid, the right panel shows the decoded text instantly.
3. If you see an error, check for invalid characters or missing padding (=).
4. Click “Copy Output” to copy the decoded result.
5. Use “Sample” to load a quick example and verify your environment.
6. Use “Clear” to reset and paste another string.

Tips

• Remove spaces and newlines—pure Base64 is continuous.
• If padding is missing, try adding one or two = at the end.
• To pretty‑print JSON after decoding, open it in JSON Viewer.

Troubleshooting

• “Invalid Base64” → Input contains characters outside A‑Z, a‑z, 0‑9, +, /, or bad padding.
• Output is garbled → The original content might be binary; this tool decodes to text only.
• Empty output → Input is empty or whitespace only; paste a valid string.
• Slow with long strings → Decoding is fast, but very large blobs can take a moment to render.