Most base64 encode tools send your data to a remote server. That means your files, API keys, and private content pass through someone else's infrastructure. encodedecode.app is different: every base64 encode and base64 decode operation runs in your browser using native btoa(), atob(), and TextEncoder. Zero outbound requests.
Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It is commonly used to encode binary data — such as images or files — for transmission over text-based protocols like email or HTTP. base64 encode operations increase size by approximately 33%.
Switch to Decode mode using the toolbar above. Paste your Base64 string into the left panel and the decoded output appears instantly on the right. encodedecode.app supports standard Base64, URL-safe Base64 (with - and _ instead of + and /), and handles padding automatically.
No. All base64 encode and decode operations run entirely in your browser using native JavaScript APIs (btoa, atob, TextEncoder). Your data never leaves your device. You can verify this by opening DevTools → Network tab — zero outbound requests during encoding.
Standard Base64 uses + and / as characters 62 and 63, and = for padding. These characters have special meanings in URLs. Base64URL (also called URL-safe Base64) replaces + with -, / with _, and omits padding. Use the URL-safe toggle to switch between formats.
Yes. Drag and drop any file onto the input panel to base64 encode it. The tool uses the FileReader API to read the file locally — it is never uploaded. After encoding, you can see the full data URL (data:mime;base64,...) and download the result. Image files show a thumbnail preview.