What it does
Encoding takes your text as UTF-8 bytes and writes them in Base64. Decoding reverses it. URL-safe mode swaps + and / for - and _, which is what web tokens and many web addresses use.
When you need it
Developers use Base64 to put small files or binary values inside JSON, HTML, CSS or email. Because 3 bytes become 4 characters, the result is about a third larger than the original. To encode a whole picture use the image to Base64 tool, to read a token use the JWT decoder, and to tidy data use the JSON formatter.
Frequently asked questions
What is Base64?
Base64 writes binary data using 64 safe text characters (A–Z, a–z, 0–9, + and /), so it can travel through systems that only accept text, like email or JSON.
Is Base64 encryption?
No. Anyone can decode it. Never use it to hide passwords or secrets.
Why does decoding fail?
The text may contain characters outside the Base64 alphabet, be missing its padding (=), or not be Base64 at all. Make sure you pasted the whole value.