Base64URL Encoder

Encode text to URL-safe Base64 strings without +, /, or = characters for web URLs, JWTs, and query parameters.

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.

Standard Base64 vs. Base64URL

Standard Base64 uses the '+' and '/' characters, which have special meanings in URLs (representing spaces and directory separators, respectively). If you pass standard Base64 data in a URL query parameter, it can become corrupted.

Base64URL encoding solves this by replacing '+' with '-' (dash) and '/' with '_' (underscore), and optionally removing the '=' padding. This makes the resulting string completely safe to include in URLs and filenames.

Frequently Asked Questions

Search below or browse through our most commonly asked questions.

Base64URL is a variant of Base64 encoding defined in RFC 4648 §5 that replaces '+' with '-' and '/' with '_', and omits '=' padding characters to make the output safe for URLs and file systems.
Standard Base64 contains '+' and '/' which have special meanings in URL query strings and path segments. Base64URL avoids percent-encoding and URL corruption.
Yes! All encoding happens 100% client-side in your web browser. No data is ever sent to a server.

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