Drop the files, drag them into order, get one document. Your PDFs are combined by your own browser — they never travel anywhere.
The output follows the list order exactly — drag rows (or use the arrows) before merging. Bookmarks and internal links of the source files don’t survive combination; pages, their content and their rotations do.
Fine. Each page keeps its own dimensions — an A4 report followed by a landscape spreadsheet followed by a phone scan stays exactly that.
Really. The PDF engine is JavaScript running in your browser tab — your file is opened from your disk into your machine’s memory, reassembled there, and saved back to your disk. Our server serves the page and the engine script, then stops being involved; you can watch the network tab, or cut your connection after the page loads and everything still works. For contracts, medical records, payslips — the files people actually need PDF tools for — that is the entire point.
Your device’s memory — there is no page cap, file cap, daily quota or account. A 200-page report is nothing. A 500 MB scanned tome will make a phone sweat; a laptop handles it. If it fits in your browser, it works.