TL;DR: Upload a background PDF and a foreground PDF — download a copy with foreground stamped over every background page.
Overlay PDF pages online — layer one PDF document on top of another. Perfect for adding letterhead, branded backgrounds, or watermark stamps to existing PDFs.
Overlay PDF is part of PrivaTools — a free, open-source alternative to iLovePDF, Smallpdf, and Adobe. Server-side tools process your file in an isolated container and discard it immediately; many tools never upload at all and run entirely in your browser.
Overlay PDF pages online — layer one PDF document on top of another. Perfect for adding letterhead, branded backgrounds, or watermark stamps to existing PDFs. Use it when you need a quick, private, no-account way to handle a pdf in the browser, or when you want an auditable open-source alternative to iLovePDF, Smallpdf, Adobe Acrobat, PDF24, and Sejda. The page at /tool/overlay is designed for one clear job: upload or provide the input, choose only the options that matter, and download the result without creating an account or passing through a sales funnel.
PDF operations that need server-side libraries run inside the PrivaTools container and return a fresh download; browser-only PDF helpers stay on-device. Temporary input and output files are not used for analytics, model training, advertising profiles, or product telemetry. The public demo uses anonymous page-view analytics only; file bytes, extracted text, filenames, passwords, signatures, and generated results are outside that analytics path. If your organization needs stricter controls, you can self-host all 214 PrivaTools utilities and keep processing on your own infrastructure.
Before running Overlay PDF, confirm that the source file opens correctly and that you have permission to process it. Keep an untouched original, run one operation at a time when quality matters, and use Pipeline when you want repeatable multi-step output. For sensitive material, review the downloaded result before sharing it. For large files, give the browser time to finish the download and avoid refreshing the page mid-run. If a password, damaged upload, unsupported codec, or malformed document blocks processing, PrivaTools returns a plain-language error so you can pick the next recovery step instead of guessing.
Overlay PDF is intentionally narrow: it does one pdf task and hands the result back as a normal download. That makes the output easy to inspect, rename, archive, attach to email, or feed into another tool. If you need a repeatable workflow, save the page, bookmark a Pipeline recipe, or self-host the API so the same steps can run from internal scripts. The interface avoids accounts and cloud folders on purpose: the safest default for private files is to process only the current request, return the result, and leave long-term storage under your control.
Overlay PDF runs in any modern browser on Windows, macOS, Linux, Android, and iOS — there is nothing to install, no extension to add, and no desktop app to keep updated. Because the interface is a single page, you can bookmark it, send the link to a colleague, or open it on a phone and get the same result you would on a laptop. There are no watermarks stamped onto your output, no sign-in wall before the download, and no paid tier that unlocks the “real” version later — the Overlay PDF you see is the complete tool. For teams that would rather keep everything in-house, the same endpoint ships in the MIT-licensed, self-hostable build, so you can run it behind your own firewall with identical behaviour and no outbound calls. That combination — instant in the browser for individuals, fully self-hostable for organizations — is what keeps a private file genuinely private from upload to download.
Merge concatenates files page-by-page. Overlay composites pages on top of each other — useful for adding letterheads, watermarks-from-PDF, or repeating templates.
By default it applies cycle-wise: if the overlay has 3 pages and the base has 10, the overlay repeats. For one-time overlay, use a base + overlay of equal length.
Yes — PDF supports transparency and the overlay's alpha is honored. White rectangles still cover what's beneath; transparent regions show base content through.
See how PrivaTools compares to iLovePDF, Smallpdf, Adobe Acrobat, and other free PDF tools.