Base64URL Encoder & Decoder

Free Base64URL Encoder & Decoder that works offline

Use the URL-safe Base64 variant common in JWTs and web protocols. It replaces plus and slash characters and usually omits trailing padding.

What this base64url encoder & decoder does

Base64URL uses the same underlying byte representation as standard Base64 but changes characters that have special meaning in URLs. Decoding restores missing padding before converting bytes back to UTF-8.

How to use the Base64URL Encoder & Decoder

1. Enter or paste UTF-8 text or a Base64URL-encoded value into the tool.
2. Adjust the available options so they match the format and result you need.
3. Choose Encode or decode Base64URL and review a URL-safe encoded string or decoded Unicode text before using it.
4. Copy or download the result, then clear the page if the input was sensitive.

Common uses

• Inspecting JWT header and payload segments
• Encoding small URL-safe values
• Testing OAuth and web protocol examples
• Comparing standard Base64 with Base64URL

Private processing and offline access

This tool does not submit your input to a conversion server. Processing takes place inside the browser using local JavaScript and standard Web APIs. After the PWA has been installed or cached, the page and its core features remain available without an internet connection. Closing or clearing the page removes unsaved input; the tool does not create an account or cloud history.

Tips for accurate results

• Base64URL is encoding, not encryption.
• JWT signatures must be verified separately.
• Use the main Base64 tool for standard plus-and-slash alphabet data.

Frequently asked questions