Developer Tools
Base64 Encoder
Encode text or any file to Base64 right in your browser. Toggle URL-safe mode for JWTs, data URLs and other contexts where + and / are not allowed. Files are turned into a ready-to-use data URL via FileReader — nothing is uploaded.
Your input is processed locally in your browser. It is not uploaded to Dueneo.
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How to use
- 1
Choose a mode
Use Text → Base64 for strings, or File → Data URL to encode a binary file as a self-contained data: URL.
- 2
Toggle URL-safe mode if needed
URL-safe Base64 swaps + and / for - and _ and removes padding. Use it for JWTs, query strings and tokens.
- 3
Encode
Click Encode (text tab) or drop a file (file tab). The output is generated locally with the browser's FileReader and btoa.
- 4
Copy or save
Use Copy to put the result on the clipboard, or Save to download it as a text file.
Common use cases
- Encode credentials or API tokens before storing them in a URL.
- Generate a data URL to inline a small image or font in HTML or CSS.
- Produce URL-safe Base64 for a JWT payload or signed token.
- Quickly inspect the Base64 representation of a string for debugging.
Limitations
- Files larger than 1 MB are rejected to keep memory usage safe.
- The text encoder uses UTF-8 — non-ASCII characters are encoded correctly.
- Base64 is not encryption. Treat it as an encoding, not a security boundary.