Base64URL

What Base64URL does

Base64URL encode/decode; also bytes and length.

Practical limit for Base64URL: Bad decode fails. That is why output can differ from heavy desktop Developer software. Read the tool-specific note again: Base64URL encode/decode; also bytes and length.

How to use Base64URL

1. Keep this tab on Base64URL (/developer/base64url). Pasting into the wrong Developer tool (for example Base64 Encode / Decode) changes the job.
2. Paste or type the input Base64URL expects. Path hint: developer · base64url. Base64URL with bytes.
3. Apply the Base64URL action only. URL Encode / Decode is a different transform (Percent-encode or decode a string (component or URI).). Base64URL encode/decode; also bytes and length.
4. Copy the output of Base64URL if you need it elsewhere. Size/complexity still follows: Bad decode fails.
5. If the text job is actually Encode or decode UTF-8 text as Base64 or Base64URL., leave Base64URL and open Base64 Encode / Decode.

When not to use Base64URL

Skip Base64URL when a neighbor tool matches better — start with Base64 Encode / Decode or URL Encode / Decode — or when the description already warns the job will fail. In the tool’s own words: Base64URL encode/decode; also bytes and length.

Questions about Base64URL

What does Base64URL do that other Developer pages on this site do not?

Base64URL encode/decode; also bytes and length. Short version: Base64URL with bytes.

Does Base64URL upload my file or text to Tool-You servers?

No. Base64URL runs in this browser tab. Files stay on the device. Limit note: Bad decode fails.

Should I use Base64 Encode / Decode instead of Base64URL?

Use Base64URL when you need Base64URL with bytes. Use Base64 Encode / Decode when you need Encode or decode UTF-8 text as Base64 or Base64URL. They share a category (Developer) but not the same job.

What are the limits of Base64URL?

Bad decode fails. Also: Base64URL encode/decode; also bytes and length.