base64-converter

Encode text to Base64, or decode Base64 back to plaintext. Handles UTF-8 correctly (accents, emoji, non-Latin scripts) and supports the URL-safe variant used in JWTs and query strings.

client-side only UTF-8 safe URL-safe variant

input

Drag & Drop a file here to convert to Base64, or click to upload.

URL-safe (use - and _ instead of + and /, no padding)

output

Result appears here.

// UTF-8 handling

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The browser's built-in btoa()/atob() only handle Latin-1 (single-byte) text and throw on anything outside that range — meaning accented characters, emoji, or non-Latin scripts break them directly. This tool encodes text as UTF-8 bytes first, then Base64-encodes those bytes, matching how Convert.ToBase64String(Encoding.UTF8.GetBytes(...)) behaves in .NET — so text round-trips correctly regardless of character set.

// when you need the URL-safe variant

Standard Base64 uses +, /, and = padding — all three have special meaning in URLs and need escaping if used in a query string or path segment.
URL-safe Base64 replaces + with - and / with _, and drops the = padding entirely — this is exactly the encoding used in JWT segments and many API tokens.
The two variants encode different symbols for the same bytes — always decode with the same variant that was used to encode, or decoding will fail or produce garbage.