Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text. Runs entirely in your browser — nothing is sent to any server.
Frequently Asked Questions
What is Base64 encoding? ▼
Base64 is an encoding scheme that converts binary data into a string of ASCII characters using a 64-character alphabet (A–Z, a–z, 0–9, +, /). It was designed to safely transmit binary data over systems that only handle plain text — such as email (MIME), HTTP headers, and JSON payloads. It encodes every 3 bytes of input as 4 Base64 characters, increasing size by approximately 33%.
Is Base64 the same as encryption? ▼
No. Base64 is an encoding scheme, not encryption. It is fully reversible and provides no security — anyone can decode a Base64 string instantly without a key. Do not use Base64 to protect sensitive data. For security, use proper encryption algorithms such as AES-256 or RSA. Base64 is only useful for encoding binary data as text for transmission.
What is URL-safe Base64? ▼
Standard Base64 uses the characters + and /, which have special meaning in URLs. URL-safe Base64 (also called Base64url, defined in RFC 4648) replaces + with - and / with _, making the encoded output safe to include in URLs and filenames without percent-encoding. This is commonly used in JWT tokens and OAuth flows.
Is my data sent to a server when I use this tool? ▼
No. All encoding and decoding is performed locally in your browser using JavaScript's btoa() and atob() functions. Nothing you type or paste is ever transmitted to our server. This makes the tool safe for encoding sensitive strings such as API credentials or configuration values.
Where is Base64 encoding commonly used? ▼
Base64 is used extensively in: HTTP Basic Authentication headers (credentials encoded as Base64), embedding images in HTML or CSS as data URIs, JSON Web Tokens (JWT), email attachments (MIME encoding), storing binary data in JSON APIs, and encoding binary files for transmission over text-based protocols. It is one of the most universally used encoding formats in web development.