CodesBeautify

Base64 to HTML Converter

Decode Base64 back into HTML markup, and render it in a sandboxed frame when you want to see the result.

Base64
HTML
Runs locally in your browser

About the Base64 to HTML Converter

Email templates, CMS exports and messaging APIs routinely wrap a chunk of markup in Base64 so it survives a JSON field or a database column. Reading that blob is impossible until it is decoded. Paste it here and the original markup appears with HTML syntax highlighting, indentation intact, ready to copy into an editor.

The optional preview switch renders the decoded markup inside a sandboxed frame instead of printing it. Scripts cannot run and the frame has no access to this page, so opening markup from an untrusted source will not do anything to your session. Turn the switch off again to get the source back for copying.

Decoding is strict about what counts as text. If the bytes contain a run of control characters, meaning the Base64 was really a zip or an image rather than markup, the tool says so instead of filling the pane with unreadable symbols. A data:text/html;base64, prefix is accepted and removed, whitespace and newlines inside the string are ignored, and the URL-safe alphabet works too.

Once you can read the markup, HTML Formatter tidies its indentation and HTML Viewer gives it a full page preview.

How to use

  1. Paste the Base64 blob into the left pane.
  2. Read the markup on the right, or tick Render the markup to see it laid out.
  3. Copy the source, or use Download to save it as an .html file.

Common questions

Is the rendered preview safe?
Yes. It runs in a sandboxed frame with scripts disabled and no access to this page, so untrusted markup cannot reach your data.
It says the bytes are binary. What does that mean?
The Base64 held a file rather than markup. Use Base64 to File to save it, then open it with the right application.
Do I need to strip the data URI prefix?
No. A data:text/html;base64, prefix is detected and removed automatically.
Will the decoded markup keep its line breaks?
Yes. Base64 preserves every byte, so the indentation and newlines come back exactly as they were encoded.