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Base64 URL Encoder

URL-safe Base64 variant used in JWTs.

Plain text
Base64URL
SGVsbG8sIHdvcmxkIQ

Base64URL swaps + for -, / for _, and drops the = padding so the result is safe in URLs and JWTs.

About

Base64 URL replaces + and / with - and _ and drops the = padding. Used in JWTs, OAuth tokens, and URL parameters where standard Base64 would break.

How to use

  1. Paste your text or Base64 URL string.
  2. See the encoded or decoded result.

FAQ

Why does standard Base64 break in URLs?+

Plus and slash are reserved characters in URLs. They get URL-encoded as %2B and %2F, which doubles the length and breaks parsers.

Where is this used?+

JWT (header, payload, signature are all Base64URL). OAuth state parameters. Data URLs in some contexts.