Base64 Encoder / Decoder for Windows

A free encoding workbench for Windows — far more than just Base64. Encode, decode, inspect and transform text and files across many formats, chain transforms into a pipeline, decode JWTs, preview images, diff text, and process whole folders. Everything runs offline, with no data ever leaving your machine.

Download Desktop Version 2.0

Free on the Microsoft Store — no subscription, no ads.

Features

🔤 Many Encoding Formats

Base64 (Standard, URL-safe, MIME, PEM), Base32 (RFC 4648 & Crockford), Base58 (Bitcoin, Ripple, Flickr), Base85 (Ascii85 & Z85), Hex, URL encoding, HTML entities, and ROT13.

🔎 Smart Detect

Not sure what you're looking at? Paste a mystery string and the app recognises the format — Base64, Hex, a JWT, a data URI, and more — then decodes it for you automatically.

🔗 Transform Pipeline

Chain steps together and run them in one go — for example URL-decode → Base64-decode → Gunzip → pretty-print JSON. Add, reorder and remove steps, with Gzip / Deflate / Brotli compression and ready-made presets.

🪪 JWT Decoder

Paste a JSON Web Token to see its header and payload as readable JSON, plus a summary of its timing claims — including whether it has expired.

📄 File & Batch Processing

Encode or decode single files with a progress bar and cancel, or whole folders at once with per-file status and an overwrite policy. Drag-and-drop supported; large files stream in chunks.

🛠️ Developer Tools

Build or read an Authorization: Basic header, and turn a Base64 value into ready-to-paste Python, JavaScript, C#, cURL, or <img> snippets.

🖼️ Image Preview & Diff

Render an image straight from a Base64 string or a data: URI, and compare two pieces of text side by side with line-by-line colour highlighting.

👀 Folder Watch & History

Point the app at a folder and have new files encoded or decoded automatically as they arrive. A history list keeps your recent operations between sessions.

🎨 Light & Dark Themes

A clean, professional light theme with a one-click dark-mode toggle and a custom icon set throughout. Your theme and default options are remembered between sessions.