Merge PDF

When you merge PDFs in SwitchPDF, each file is parsed page by page using the open-source pdf-lib library. We extract every page object — including its text streams, font references, embedded images, and form fields — and append them to a new output document in the order you specified. Bookmarks and metadata from the first file are preserved as the merged document's outline.

Because we operate on the underlying PDF objects directly (not by re-rendering the page as an image), the merge is lossless. A 300-DPI scan stays at 300 DPI. A document with selectable, searchable text stays selectable and searchable. Fonts that are embedded in the source PDFs remain embedded, so the merged file renders identically on every device.

Most online merger tools strip annotations, flatten form fields, or recompress images "to save space." SwitchPDF deliberately does not — the output is byte-for-byte the same quality as your inputs, just stitched together. The trade-off is a slightly larger file, which you can shrink afterwards using our Compress PDF tool if needed.

The merge happens in your browser session via a single HTTPS request. We do not store, index, or share your files. After 15 minutes the upload and the merged output are both permanently removed from disk by an automatic cleanup job.