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Base64 output
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What is Base64 encoding?
Base64 is a binary-to-text encoding scheme that converts binary data into a string of ASCII characters. It represents binary data using 64 printable characters (A–Z, a–z, 0–9, +, /). Base64 is widely used in web development to embed images in HTML/CSS, encode authentication credentials in HTTP headers, and transmit data in contexts that only support text.
The URL-safe variant replaces + with - and / with _ to make encoded strings safe for use in URLs and filenames without additional encoding. This tool processes everything in your browser — your data is never transmitted.
Frequently asked questions
What is Base64 used for?
Base64 is used to embed binary data in text formats — images in HTML/CSS data URIs, credentials in Basic Auth headers, attachments in email MIME encoding, and binary data in JSON APIs.
Is Base64 the same as encryption?
No. Base64 is encoding, not encryption. Anyone can decode a Base64 string without any key. It is used for data transport, not security.
What is URL-safe Base64?
Standard Base64 uses + and / which have special meaning in URLs. URL-safe Base64 replaces + with - and / with _ making it safe to use in URLs and filenames without percent-encoding.
Why does Base64 add padding with = signs?
Base64 encodes 3 bytes into 4 characters. If the input length is not divisible by 3, = signs are added to pad to the nearest multiple of 4.
Common use cases
Embed images in HTML/CSS (data URIs)
HTTP Basic Auth headers
Email MIME attachments
JWT token payloads
Binary data in JSON APIs
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