HTML Email Attachment Preview by 박정섭

Bank statements, credit card bills, insurance documents, government notices, tax invoices — a surprising share of email attachments arrive not as PDF, but as HTML. Click one in your inbox: PDFs and images get an inline preview with a built-in print button, but HTML attachments force you to download them and open from your PC.

· Just to read it: download → open the folder → double-click → go back to the folder and delete
· To print or save as PDF: download → open → print → delete the downloaded file

A single statement, a single receipt — and you go through these steps every time.

HTML Email Attachment Preview solves this. HTML attachments open inline in your mailbox just like PDFs do, and you can print or save as PDF right from the preview. No downloads, no folder cleanup.

■ What it does

📄 Inline HTML attachment preview
Renders HTML attachments directly inside your mailbox — no download, no temporary files. One click and the content is on screen.

🔐 Compatible with Korean security mail
Automatically handles password-protected HTML emails commonly used by Korean banks and card issuers, so they render correctly inside the preview.

🛡 Sandboxed isolation
Every attachment renders inside a sandboxed extension page with an opaque origin. HTML scripts inside cannot read your mail page, send authenticated requests, or reach extension APIs.

✅ Per-sender allowlist
The first time you receive an HTML attachment from a sender, a non-blocking banner asks: "Render once / Always trust this sender / Dismiss." Trusted senders open instantly from then on.

⚡ Auto-allow mode
For users already familiar with the senders they receive HTML statements from, the popup offers an "Auto-render all HTML attachments" toggle. Skip the per-sender confirmation entirely.

🖨 Print or save as PDF in one click
A print button on the preview window lets you print to paper or save as PDF immediately. The download → open → print → delete cycle becomes a single click — especially useful for filing statements and saving receipts.

■ Supported mail services

· Gmail
· Naver Mail
· Daum Mail
· Kakao Mail

■ Who it's for

· Anyone who receives bank or credit card statements as HTML attachments every month
· People who get insurance policies or brokerage certificates as HTML
· Recipients of government and public-institution notices delivered as HTML
· Sole proprietors and freelancers who get tax invoices from clients as HTML
· Anyone tired of the download → open → delete dance
· Anyone who wants to keep their Downloads folder clean

■ Privacy

This extension does not transmit your data anywhere.

· No analytics, no tracking, no remote servers
· Your trusted-senders list is stored only in your browser's sync storage
· HTML attachments are rendered only inside a sandboxed page on your own machine — no content is sent outside
· The attachment download itself uses the normal API of the mail service you're already logged into

■ How to use

After installing, just open a message with an HTML attachment in Gmail / Naver Mail / Daum Mail / Kakao Mail. No setup, no login required.

For senders you haven't approved yet, a one-time confirmation banner appears. Choose "Always trust this sender" and future attachments from them open automatically.