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Base64 Encoder / Decoder

Encode or decode Base64 with full UTF-8 and URL-safe variants.

Input

Output

Base64 encoder and decoder with full UTF-8 support

Base64 is the standard way to encode binary or non-ASCII text into a 64-character ASCII alphabet so it can travel through systems that only handle text — HTTP headers, JSON strings, data URIs, JWT segments. This tool encodes and decodes Base64 with proper UTF-8 handling and an optional URL-safe variant for tokens, query parameters, and JWT.

Standard vs URL-safe

Standard Base64 uses +, /, and = padding — three characters that have special meaning in URLs. The URL-safe variant (RFC 4648 §5) replaces + with -, / with _, and drops the padding. JWTs and many modern APIs use URL-safe Base64 — toggle the option here if your input doesn't decode as standard.

UTF-8 done right

The naive btoa(input) call fails on any non-ASCII character ("InvalidCharacterError"). This tool encodes via btoa(unescape(encodeURIComponent(s))) and decodes via decodeURIComponent(escape(atob(s))), which round-trips emoji, CJK characters, and accented Latin correctly. So カフェ encodes to 44Kr44OV44Kn and back, exactly like in your backend.

Common use cases

Inspect a JWT segment — copy the payload chunk and decode (or use our JWT Decoder).
Build a data URI — encode an SVG or small PNG to embed inline in CSS or HTML.
Read an HTTP Basic Authorization header — decode dXNlcjpwYXNz to user:pass.
Round-trip a config secret through Kubernetes Secrets, which expects values Base64-encoded.

Privacy

All encoding happens in your browser via the built-in btoa/atob functions. The tool never sends your input to a server.

Related tools

FAQ

Why does my Base64 fail to decode?

Common causes: missing padding (we add it automatically), URL-safe characters (toggle the URL-safe option), or stray whitespace pasted from email. Strip whitespace and try again.

Is Base64 encryption?

No. Base64 is encoding, not encryption — anyone can decode it. Never use Base64 to 'hide' a secret.

Will it handle emoji and non-ASCII characters?

Yes. Encoding wraps btoa with proper UTF-8 conversion, so every Unicode character round-trips correctly.

What's the difference between standard and URL-safe Base64?

URL-safe replaces + with - and / with _, and drops = padding. JWTs and many tokens use URL-safe.