Base64 Encoder/Decoder

Base64 converts binary data into a text-safe ASCII string using 64 printable characters (A-Z, a-z, 0-9, +, /). It's used to embed binary data in text-based formats like JSON, HTML, CSS, and email. Tip: Base64 encoding increases the data size by approximately 33%, so it's best suited for small assets.

Common uses include embedding small images as data URIs in CSS/HTML (saving HTTP requests), encoding binary data for JSON APIs, and encoding file attachments in email (MIME). Tip: for images under 2-5 KB, Base64 data URIs are often faster than separate HTTP requests due to reduced round-trips.

No. Base64 is an encoding scheme, not encryption. Anyone can decode Base64 text back to the original data instantly. Never use Base64 to 'hide' passwords, tokens, or sensitive information. Tip: if you need to protect data, use proper encryption (AES, RSA) or hashing (SHA-256) — not encoding.

Standard Base64 uses + and / characters which are unsafe in URLs. Base64url replaces them with - and _ and omits padding (=). It's used in JWTs, URL parameters, and filename-safe contexts. Tip: most modern libraries support both variants — check your runtime docs for URL-safe options.

Use btoa() and atob() for simple strings, or the Buffer API in Node.js: Buffer.from(str).toString('base64'). For binary data or Unicode strings, first encode to Uint8Array with TextEncoder, then convert. Tip: btoa() only handles Latin-1 characters — for Unicode text, encode to UTF-8 bytes first.