Merge PDF

Yes. We rely on qpdf’s page-level assembly (`--pages`) instead of rendering through Ghostscript or LibreOffice. Text, vectors, forms, bookmarks, and embedded fonts stay intact; only the page tree is rearranged. When you toggle the optional “lossless recompress,” we run `--stream-data=compress --object-streams=generate`, which repacks streams without changing visual content.

Use qpdf syntax: `1-3` (inclusive range), `5` (single page), `7-` or `7-z` (from page 7 to the last). Combine with commas, e.g., `1-3,5,7-`. The UI validates and normalizes input, stripping any characters outside digits, commas, dashes, spaces, and `z`.

Each job runs in `/tmp/omnvert-pdf/<jobId>/` with random UUIDs for filenames, so user-supplied names are never used as paths. Files live only for the duration of the request; once the response stream finishes, we delete the folder in a `finally` cleanup step. No long-term storage or cross-job reuse occurs.

Uploads are capped at 50 MB per PDF for these tools, with a 30s execution timeout per qpdf call. A lightweight in-memory queue limits concurrent heavy jobs (default 2) to protect CPU and memory. Large PDFs are streamed to disk rather than buffered in RAM to avoid spikes.

Internal links, outlines, and metadata are preserved because we are not rasterizing pages. Digital signatures may break if you split or merge in ways that alter the signed structure—this is expected for any structural edit. If you must keep signatures, avoid structural changes or re-sign afterward.

qpdf rewrites the PDF object graph without rendering content, so vectors, embedded fonts, and transparency stay identical. It is fast, scriptable, and stable on Linux servers, and it avoids image downsampling that visual converters often introduce. That matches Omnvert’s goal: precise, high-fidelity document tools without lossy surprises.

For merging, add files in the exact order you want and optionally constrain each file with ranges (e.g., File A: `1-5`, File B: `all`). For splitting, pick “Split by ranges” and define chapter breaks like `1-10,11-22,23-30`; you’ll receive a ZIP with one PDF per range. “Per-page” creates one PDF per page for fine-grained work.

Recompress asks qpdf to recompress streams and regenerate object streams. It can shrink PDFs that contain uncompressed streams while keeping visuals identical. It is optional because some PDFs are already optimized; when there’s nothing to gain, output size will be similar while still remaining lossless.

If you see “invalid range,” double-check for typos and keep ranges ascending. For “file too large,” trim inputs or compress separately. Password-protected PDFs are not supported. Corrupted PDFs may fail `--show-npages`; try re-saving with a viewer first. If a job times out, split the work into smaller ranges or fewer files.