Base64
Encode UTF-8 text as Base64, or decode Base64 to UTF-8 text.
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What is Base64 encoding?
Base64 is an encoding scheme that converts binary data into a string of printable ASCII characters using 64 symbols (A–Z, a–z, 0–9, +, /). It is not encryption — the data is trivially reversible. It's used wherever binary data must be transmitted over a text-only channel: email attachments (MIME), data URIs in HTML/CSS, and JWTs.
When should I use Base64?
Use Base64 when you need to embed binary data (images, certificates, binary files) inside a text format like JSON, XML, or HTML. For example, data:image/png;base64,iVBOR... embeds an image directly in a stylesheet. Do not use Base64 to 'secure' data — it provides no confidentiality.
What is the difference between standard and URL-safe Base64?
Standard Base64 uses + and / which have special meaning in URLs. URL-safe Base64 (RFC 4648) replaces them with - and _ so the result can be used directly in URLs and filenames without percent-encoding. JWTs use URL-safe Base64 without padding (=). This tool uses standard Base64.
Why does a Base64 string end with = or ==?
Base64 encodes 3 bytes at a time into 4 characters. If the input isn't a multiple of 3 bytes, padding characters (=) fill the last group to maintain the 4-character block size. One = means 2 leftover input bytes; == means 1 leftover byte.