How to use Ciphertext Decoder
- Paste the text you need to decode into the input box.
- Tune the Mode control before you decode.
- Ciphertext Decoder updates the output automatically as you type.
- Finish by choosing Copy to take the output with you.
About this tool
Ciphertext Decoder runs entirely in your browser. Ciphertext Decoder encodes or decodes Base64 on your device with no round-trip to a server.
Because it runs locally, even sensitive payloads never leave the page. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
What is Ciphertext Decoder for?
Use Ciphertext Decoder to decode your input without installing anything using the Mode control; everything happens client-side.
Does Ciphertext Decoder cost anything?
No — Ciphertext Decoder is completely free, with no sign-up and no hidden limits.
Does Ciphertext Decoder upload my data?
No — Ciphertext Decoder processes everything locally in your browser, so nothing you enter is uploaded or stored.
Is Base64 in Ciphertext Decoder URL-safe?
Ciphertext Decoder uses standard Base64 by default and runs locally, so your data is never sent anywhere.
Does Ciphertext Decoder work offline?
Once the page has loaded, Ciphertext Decoder keeps working with no network connection.