Base64 Decoder
Free online Base64 decoder — decode Base64 strings back to plain text instantly. Fast, private, and runs entirely in your browser.
What is Base64 Decoding?
Base64 decoding reverses the encoding process, converting Base64 strings back to their original form. This is essential when you need to read encoded data — whether it's from an email attachment, a data URL, a JWT payload, or an API response. Base64 decoding works by taking each group of 4 Base64 characters and converting them back into 3 bytes of original data. Many developers and security professionals use Base64 decoding daily to inspect API tokens, decode JWT payloads, and extract embedded data from URLs. Use this free online Base64 decoder to quickly convert Base64 back to readable text right in your browser.
How to Use the Base64 Decoder
- Paste your Base64-encoded text into the input field above.
- Click the Decode button to convert it back to plain text.
- Click Copy to copy the decoded text to your clipboard.
When to Use Base64 Decoding
- Inspecting JWT payload contents
- Extracting embedded data from data URIs
- Decoding API authentication tokens for debugging
- Reading Base64-encoded configuration or secrets
- Viewing the contents of MIME-encoded email attachments