A .B64 file is generally a Base64 text container so the underlying binary (PDF, PNG, ZIP, audio, etc.) is expressed in safe characters suitable for email, configs, logs, or APIs, and opening it in a text editor reveals lines of Base64 characters plus possible padding `=` or headers like `—–BEGIN …—–`, while decoding converts it back into the exact file, with telltale starts such as `UEsDB` hinting at ZIP/DOCX or `/9j/` hinting at JPEG, and Base64 making data larger without providing encryption.

A .B64 file is often just a Base64-encoded representation of another file which explains why email sends attachments as Base64, APIs return files in JSON strings, and developers embed icons or certificates directly into code or configurations, plus many backup tools export paste-ready Base64 blocks, with the end goal being that decoding restores the original binary content.

When we say a .B64 file holds Base64-encoded text, we mean the file you see isn’t the actual PDF/image/ZIP/program but a text translation of its raw bytes, because binary can break in text-only systems due to encoding or formatting changes, while Base64 converts those bytes into safe characters (`A–Z`, `a–z`, `0–9`, `+`, `/`, `=`), letting the data travel intact until you decode it back into the original usable file.

You’ll see .B64 files in places that must move binary through text-based channels, such as email attachments encoded for safe transit, APIs sending images or documents inside JSON, developers embedding icons or certificates into text formats, and export/backup tools creating copy/paste-friendly blobs, with `.b64` acting as a dependable wrapper until decoding restores the real file.

A .B64 file contains Base64-encoded content using the restricted alphabet (`A–Z`, `a–z`, `0–9`, `+`, `/`, `=`), sometimes split into multiple lines or kept continuous, and may include PEM/MIME wrappers around the payload, but the important part is that decoding the text yields the original file’s bytes, which must then be saved with the correct extension.

A practical shortcut for figuring out a .B64 file’s decoded output is reading its first Base64 characters: `JVBERi0` almost always means PDF, `iVBORw0` means PNG, `UEsDB` means ZIP/Office formats, and `/9j/` means JPEG; though not foolproof due to potential wrapping or metadata, it’s usually enough to decide whether the decoded file should be saved as `.pdf`, `.png`, `.zip`, `. If you are you looking for more about B64 file opener review the web site. jpg`, or another type.