Base64 Encoder & Decoder

Encode text to Base64 and decode it back, with correct UTF-8 handling so accented characters, Bangla and emoji survive the round trip intact.

What Base64 is for

Many systems were designed to carry plain text and nothing else. Email is the classic example: the original protocols assumed 7-bit ASCII, so anything outside that range could be mangled in transit. Base64 re-expresses arbitrary binary data using only 64 characters that travel safely everywhere. The data is unchanged in meaning, just written in a safer alphabet. The cost is size: every three bytes become four characters, so encoded data is roughly 33% larger than the original.

It is not security, and that matters

Base64 is not encryption and protects nothing. There is no key, anyone can decode it instantly, and it is trivially recognisable by its character set and padding. This is worth stating plainly because the mistake appears in real systems: credentials Base64-encoded in configuration files or request headers, treated as though they were protected. They are not. Putting a password in Base64 is equivalent to writing it out plainly, with an extra step that fools nobody.

Where decoding usually goes wrong

Standard Base64 uses + and / as its final two characters, both of which have special meaning in URLs. A URL-safe variant substitutes - and _ , and a mismatch between the two is a common cause of decode failures. Missing padding is the other. Some systems strip the trailing = characters, and stricter decoders then reject the input. If a decoded string looks corrupted while the plain ASCII parts are fine, the cause is almost always a character-encoding mismatch rather than a Base64 problem — the bytes decoded correctly but were interpreted with the wrong text encoding.

Quick tips

• Base64 is for safe transport, not confidentiality — use HTTPS for the latter.
• Data URIs suit tiny icons; the 33% overhead makes them wasteful for larger images.
• JSON has no binary type, which is why binary payloads are usually Base64 encoded.
• Whitespace and line breaks in encoded input are ignored here and decode fine.

Is Base64 encryption?

No. Base64 is an encoding format designed to transmit binary data safely over text-based protocols, not an encryption standard.