Base64 Encoder / Decoder

How to use Base64 Encoder / Decoder

1. Open Base64 Encoder / Decoder — it runs entirely in your browser with no setup.
2. Paste or type your input into the text area, or upload a file where supported.
3. Set any options you need. The result appears in the output panel — there is no upload step and no waiting on a server.
4. Review the output instantly; large inputs are handled locally without lag.
5. Copy the result to your clipboard or download it. Your data never leaves the page.

Why use Base64 Encoder / Decoder?

• 100% free with no limits, no sign-up and no watermarks.
• Private by design — your data are processed in your browser and never uploaded to a server.
• Fast and lightweight, with instant results even on a phone or a slow connection.
• Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
• Part of a full developer tools suite, so related base64 encode tasks are one click away.

What people use Base64 Encoder / Decoder for

• Encoding binary data for embedding in JSON, HTML or a data URI.
• Decoding a Base64 string from an API response or a config file.
• Inspecting the payload of a token or an encoded parameter.

Base64 Encoder / Decoder: limits and things worth knowing

• Base64 is an encoding, not encryption. Anyone can decode it instantly, so it protects nothing — its purpose is making binary data safe to transport as text.
• Encoding inflates size by about 33%, since every three bytes become four characters. This is why embedding large images as data URIs hurts page weight.
• Standard Base64 uses + and /, which have meaning in URLs. Base64url substitutes - and _ and is what JWTs and URL parameters use.
• Trailing = characters are padding to a multiple of four. Some implementations omit them, and some strict decoders then reject the input.

Is it private and secure?

Your privacy is built in. Base64 Encoder / Decoder runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.

Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.

You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.

Learn more

Is It Safe to Paste Production Data Into Online Tools? — JWTs, API responses and env files get pasted into online formatters every day. Here's what actually happens to that data and how to check before you paste.