Base64 Encode / Decode
Convert text to and from Base64.
About this tool
Base64 rewrites arbitrary bytes using 64 characters that survive systems which only expect text — email bodies, JSON strings, data URIs, HTTP headers. It is a transport encoding, not compression and not security.
Encoding and decoding both run locally, so nothing you paste is transmitted.
Common questions
Is Base64 encryption?
No, and treating it as such is a genuine security mistake. It is a reversible encoding with no key — anyone can decode it instantly. Never use it to hide a credential.
Why is my Base64 string bigger than the original?
It encodes 3 bytes as 4 characters, so output is about 33% larger. That is the cost of making binary data safe to put somewhere that only accepts text.
What is base64url and why does my JWT use it?
Standard Base64 uses + and /, which have meaning inside a URL. base64url swaps them for - and _ and drops the = padding, so the value can sit in a URL or a token segment without being re-encoded.
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