Base64URL Decoder

Decode URL-safe Base64 strings (using '-' and '_') back to plain text or standard Base64.

Last Updated: August 2026
100% Client-Side — Your data never leaves your device

URL-safe Base64 replaces + with - and / with _, and removes trailing = padding. This is used in JWT tokens, URL parameters, and cookies.

Why this tool is safe

Your data never leaves your device — everything runs in your browser.

No server uploads. Other tools send your files to their servers. Ours don't.
Zero tracking of content. We never see, store, or log anything you convert.
Works offline. Once loaded, the tool works without an internet connection.
No account required. Instantly use all tools completely free without signing up.

Decoding URL-Safe Base64

Our Base64URL Decoder takes URL-safe Base64 strings (where '+' is replaced by '-' and '/' is replaced by '_') and converts them back to plain text.

It automatically handles missing '=' padding characters, which are often stripped from Base64URL strings to make them more compact.

Frequently Asked Questions

Search below or browse through our most commonly asked questions.

Base64URL decoding converts '-' back to '+' and '_' back to '/', adds necessary '=' padding, and decodes the standard Base64 binary payload into UTF-8 text.
Yes. JWT headers and payloads are encoded with Base64URL without padding, which this tool seamlessly decodes.
No, all decoding is performed locally inside your browser.

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