Base64URL Encoder/Decoder
Encode text to URL-safe Base64 (base64url, RFC 4648 §5) or decode it back. Uses - and _ instead of + and /, optional padding — the variant used by JWTs.
Input
JWTs and most URL uses omit padding.
Output
Result
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More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/base64url-encoder-decoder \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"inputText": "subjects?_d=1",
"mode": "encode",
"padding": "false"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `base64url-encoder-decoder` tool (Base64URL Encoder/Decoder) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/base64url-encoder-decoder/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Base64URL Encoder/Decoder — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
What is Base64URL?
Base64URL (RFC 4648 §5) is Base64 with - and _ in place of + and /, and usually no = padding, so the result is safe in URLs, filenames and cookies. It is the encoding used by JWT segments.
How to use it
- Paste text (to encode) or a Base64URL string (to decode).
- Choose Encode or Decode; optionally keep
=padding when encoding. - Copy or download the result.
Decoding accepts both the URL-safe and standard alphabets, with or without padding.
Privacy
Everything runs in your browser; nothing is uploaded.
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