📦 Base64 Encoder

About the Base64 Encoder / Decoder

Base64 is an encoding scheme that converts binary data into a printable ASCII string using a 64-character alphabet (A–Z, a–z, 0–9, +, /). It is not encryption — it is purely an encoding to safely carry binary or non-ASCII data across text-based protocols such as HTTP, JSON, email (MIME), and HTML.

Common use cases

• JWTs — the header and payload segments of a JSON Web Token are Base64URL-encoded (a URL-safe variant using - and _ instead of + and /).
• Data URLs — embedding images, fonts, or other files directly in HTML or CSS: data:image/png;base64,...
• API payloads — encoding binary data such as file contents or TLS certificates for transmission in JSON fields.
• HTTP Basic Auth — the browser encodes credentials as Base64(username:password) in the Authorization header.
• Email attachments — MIME encodes binary attachments in Base64 before embedding them in email messages.

Base64 vs Base64URL

Standard Base64 uses + and / which are special characters in URLs. Base64URL replaces them with - and _, and omits the = padding, making the output safe to include directly in URLs and HTTP headers. JWT segments use Base64URL encoding.

How to use this tool

• Encode: Select Encode mode, paste your plain text, and click Encode →. The Base64 representation is shown in the output panel.
• Decode: Select Decode mode, paste a Base64 string, and click Decode →. The original text is recovered and displayed.

The tool handles standard Base64 as well as multi-byte UTF-8 text. To decode a JWT segment, you can paste it directly — the tool handles URL-safe characters automatically.