TL;DR: Upload two PDFs and download a copy that interleaves their pages (1A, 1B, 2A, 2B…) — useful for un-imposing two-sided scans.
Alternate mix PDF pages online — interleave pages from two or more PDFs for duplex scanning workflows. Combine front-side and back-side scans into the correct page order.
There is no paywall behind Alternate Mix PDF. It is part of an open-source suite of 214 tools released under the MIT license, so you can read exactly how your file is handled — or fork it and run the whole thing on a server you control.
Alternate mix PDF pages online — interleave pages from two or more PDFs for duplex scanning workflows. Combine front-side and back-side scans into the correct page order. 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/alternate-mix 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 Alternate Mix 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.
Alternate Mix 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.
Alternate Mix 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 Alternate Mix 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.
The classic case is double-sided scanning on a single-sided scanner: scan the odd pages, flip the stack, scan the even pages in reverse, then alternate-mix them with reverse-alternate.
PrivaTools alternates pages until one source is exhausted, then appends the remaining pages from the longer source at the end.
No. Bookmarks from the originals are dropped because they would point to incorrect pages after interleaving.
See how PrivaTools compares to iLovePDF, Smallpdf, Adobe Acrobat, and other free PDF tools.