Base64 Encoder
Encode text to Base64 or decode Base64 back to text, instantly and client-side.
What is Base64? Read our guide →What Base64 encoding is and is not
Base64 is an encoding scheme, not encryption. It converts binary data or text into a safe ASCII string using 64 printable characters. The output is about 33% larger than the input.
It doesn't hide data: anyone can decode it instantly. Its purpose is transport safety, embedding binary in JSON, XML, or HTTP headers that only accept text.
Standard vs URL-safe (Base64url)
Standard Base64 uses + and / characters, which are special in URLs and can break query strings. URL-safe Base64 (Base64url) replaces + with - and / with _, making the output safe for URLs, filenames, and HTTP headers.
JWT tokens use Base64url for their header and payload sections, which is exactly what the "JWT-compatible" variant here produces.
Common uses: images, auth tokens, data URIs
Developers encode images or PDFs to Base64 to embed them directly in HTML data URIs or JSON API responses, avoiding a separate file request.
Auth tokens, API keys, and session cookies are often Base64-encoded before being placed in Authorization headers. Configuration systems encode secrets to prevent accidental whitespace or special-character corruption in environment variables.