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Base64URL

URL-safe Base64 variant: replaces + / = with - _ and removes padding

Encode Decode
Chars: {{ inputText.length }}
{{ error }}
↓
Standard Base64 →

About Base64URL

Base64URL is the "URL-safe" variant of Base64, designed for transmission in URLs, file names, cookies and similar contexts. In standard Base64, + and / get escaped in URLs (becoming %2B and %2F), and the = padding often causes ambiguity.

Base64URL makes three substitutions: + → -, / → _, and removes trailing = padding. The result can be placed directly into a URL parameter without extra encoding. It is widely used in JWT (JSON Web Token), OpenID Connect, OAuth and similar protocols.

Examples

Input: Hello World

Standard Base64: SGVsbG8gV29ybGQ=

Base64URL: SGVsbG8gV29ybGQ

FAQ

Q: Can Base64URL and standard Base64 be converted to each other?
A: Yes. Just swap + ↔ -, / ↔ _, and add or remove = padding per length. The underlying data is identical.
Q: Why does JWT use Base64URL?
A: JWT is typically transmitted as a URL parameter or request header. Removing + / = prevents URL encoding from breaking the structure, ensuring the token parses reliably across environments.
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