How is this different from other online PDF tools?

Most online PDF tools send your files to a remote server for processing. This tool processes everything locally in your browser using client-side JavaScript. Your files are never transmitted to any server, which means your document content stays entirely under your control.

Are my PDF files uploaded?

No. Your files are read directly by your browser. Your files are never transmitted over the network. The tool works entirely within the browser tab you have open.

Can I verify that files are not uploaded?

Yes. Open your browser's developer tools (F12), go to the Network tab, and watch for any outgoing requests while using the tool. You will see no file data leave your browser. The site may record an anonymous page-view count, which never includes your files and can be disabled.

Does this tool work offline?

Yes, once the page has loaded the tool processes your files entirely in your browser; tool functionality needs no network connection. You can disconnect from the internet and continue using it.

What happens when I refresh the page?

Because nothing is stored on a server, refreshing the page clears your current session. Any files you had selected will need to be selected again.

Does this tool store my files?

No. Files are held in browser memory only for as long as the page is open. Closing or refreshing the page discards them. Nothing is written to disk by the tool, and nothing is sent to a server.

Can this tool unlock password-protected PDFs?

No. This tool does not attempt to remove or bypass PDF password protection. If you know the password, the Unlock PDF tool on this site can remove it locally; then this tool can process the file.

What technologies does this tool use?

This tool uses client-side JavaScript and pdf-lib to embed your file inside the PDF entirely within your browser — your files never leave your browser.

Does this tool use WebAssembly?

No. This tool uses client-side JavaScript and pdf-lib for local PDF structure editing. No WebAssembly is involved.

How do I attach a file to a PDF here?

Pick your PDF with the file picker, then choose the file you want to embed and, if you like, type a short description. Click the attach button and a new PDF with the embedded file is offered as a download, all handled in your browser.

Can I attach any type of file, not just another PDF?

Yes. The file picker for the attachment accepts any file type, and the chosen file is embedded as-is using its detected MIME type (falling back to a generic binary type if none is known). It is stored inside the PDF rather than converted, so images, spreadsheets, archives, and more all work.

Why can't I see the attached file when I open the PDF?

The file is embedded as a PDF attachment, which most viewers show in a separate attachments or paperclip panel rather than on the page itself. Some lightweight viewers do not display embedded files at all, so try a viewer like Acrobat to find it. Note that the attachment is embedded in readable form, not encrypted.

Is the Attach File to PDF tool free to use?

Yes — embedding a file inside a PDF is completely free, no account or sign-up needed, and you can attach files to as many PDFs as you like, and it always will be free. Because the entire process runs inside your own browser using pdf-lib, neither the PDF nor the file you're embedding is ever sent to a server — your data stays on your device from start to download.

Attach a File to a PDF Privately — Embed Files in Your Browser

Select a PDF and a file to embed; the file is attached inside the PDF and offered as a download — all processed locally in your browser with no upload.

Quick answer

What it does: Select a PDF and a file to embed; the file is attached inside the PDF and offered as a download — all processed locally in your browser with no upload.
Free?: Yes — 100% free, no account or sign-up.
Files uploaded?: No — everything is processed in your browser.
Works offline?: Yes — once the page has loaded.
Best for: A consultant embeds the supporting Excel data file inside a PDF report so both files travel together.
Good to know: Attachments are visible to anyone who opens the PDF in a viewer that supports embedded files; this does not encrypt the attached file.

How it works

Select a PDF file from your device using the file picker.
Both the PDF and the file to attach are read into browser memory — no data leaves your browser.
Choose any file to embed and, optionally, a description.
pdf-lib embeds the file as a PDF attachment in your browser.
The updated PDF is offered as a download directly from your browser.

When to use this tool

A consultant embeds the supporting Excel data file inside a PDF report so both files travel together.
A researcher attaches the raw CSV dataset to a published findings PDF for reproducibility.
An architect includes a DWG drawing file inside a PDF specification so contractors have everything in one file.
Attachments are visible to anyone who opens the PDF; some lightweight viewers do not display embedded files.

Frequently asked questions

How is this different from other online PDF tools?: Most online PDF tools send your files to a remote server for processing. This tool processes everything locally in your browser using client-side JavaScript. Your files are never transmitted to any server, which means your document content stays entirely under your control.
Are my PDF files uploaded?: No. Your files are read directly by your browser. Your files are never transmitted over the network. The tool works entirely within the browser tab you have open.
Can I verify that files are not uploaded?: Yes. Open your browser's developer tools (F12), go to the Network tab, and watch for any outgoing requests while using the tool. You will see no file data leave your browser. The site may record an anonymous page-view count, which never includes your files and can be disabled.
Does this tool work offline?: Yes, once the page has loaded the tool processes your files entirely in your browser; tool functionality needs no network connection. You can disconnect from the internet and continue using it.
What happens when I refresh the page?: Because nothing is stored on a server, refreshing the page clears your current session. Any files you had selected will need to be selected again.
Does this tool store my files?: No. Files are held in browser memory only for as long as the page is open. Closing or refreshing the page discards them. Nothing is written to disk by the tool, and nothing is sent to a server.
Can this tool unlock password-protected PDFs?: No. This tool does not attempt to remove or bypass PDF password protection. If you know the password, the Unlock PDF tool on this site can remove it locally; then this tool can process the file.
What technologies does this tool use?: This tool uses client-side JavaScript and pdf-lib to embed your file inside the PDF entirely within your browser — your files never leave your browser.
Does this tool use WebAssembly?: No. This tool uses client-side JavaScript and pdf-lib for local PDF structure editing. No WebAssembly is involved.
How do I attach a file to a PDF here?: Pick your PDF with the file picker, then choose the file you want to embed and, if you like, type a short description. Click the attach button and a new PDF with the embedded file is offered as a download, all handled in your browser.
Can I attach any type of file, not just another PDF?: Yes. The file picker for the attachment accepts any file type, and the chosen file is embedded as-is using its detected MIME type (falling back to a generic binary type if none is known). It is stored inside the PDF rather than converted, so images, spreadsheets, archives, and more all work.
Why can't I see the attached file when I open the PDF?: The file is embedded as a PDF attachment, which most viewers show in a separate attachments or paperclip panel rather than on the page itself. Some lightweight viewers do not display embedded files at all, so try a viewer like Acrobat to find it. Note that the attachment is embedded in readable form, not encrypted.
Is the Attach File to PDF tool free to use?: Yes — embedding a file inside a PDF is completely free, no account or sign-up needed, and you can attach files to as many PDFs as you like, and it always will be free. Because the entire process runs inside your own browser using pdf-lib, neither the PDF nor the file you're embedding is ever sent to a server — your data stays on your device from start to download.