Base64 Encode and Decode Online

Worked example

Example: decode `SGVsbG8gV29ybGQ=` to `Hello World` when debugging a JWT header or API response field.

When to use this

• Debugging API responses with Base64 fields.
• Building data URLs for small inline assets.
• Teaching encoding in workshops.

Common examples

• UTF-8 email header value → Base64 for debugging MIME parts.
• Small JSON claim → Base64 segment inspection before JWT assembly.
• Data URL prefix stripped → decode image bytes from `data:image/png;base64,...` payloads.
• Small SVG icon → data URL for inline HTML email test.
• UTF-8 string with emoji → Base64 for API fixture matching production encoding.

Common mistakes

• Confusing Base64 with encryption.
• Decoding binary data as UTF-8 text and getting mojibake.
• Forgetting URL-safe Base64 variants use different alphabet.

How it works

Encodes plain text to Base64 or decodes Base64 back to text on your device using standard encoding. Large inputs are processed locally.

Limitations

Results are based on the inputs you provide and may not cover every edge case. This tool is for general use and is not professional advice.

Privacy and file handling

Your image stays on your device and is not uploaded.