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Base64 URL-Safe Encoding: Why + and / Break URLs

Understand Base64url encoding: why standard Base64 breaks URLs, how to convert, and where it is used (JWTs, URL parameters).

The Problem

Standard Base64 uses + and / which have special meanings in URLs. + becomes a space, / is a path separator.

The Solution: Base64url

Standard: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\nURL-safe: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_

JWTs use Base64url without padding. Decode them with our JWT Decoder.

Try It Free

Use our free online tool — 100% client-side, no data leaves your browser.

Open Base64 Tool

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