Oncea file clinic

PDF clinic

Merge, split, or rewrite PDFs in this tab. Nothing is uploaded. No account, no watermark, no email wall. About 80 MB total, desktop first.

Before you start. About 80 MB is the ceiling. Desktop Chrome or Firefox is the setup that works. iPhone and large files may fail — the work stays in this tab, and the browser can run out of memory.

Drop two or more PDFs, put them in order, download one file. Stays in this tab.

How to merge PDFs on this page

  1. Read the limit note above the square. About 80 MB total. Desktop Chrome or Firefox. iPhone and large files may fail.
  2. Choose Merge. Drop two or more .pdf files on the square, or click it and pick them. Drop again to add more. Nothing leaves the tab.
  3. Use Up and Down to put the files in the order you want. The first file is the first pages of the result.
  4. Click Merge PDFs. pdf-lib copies every page into one new file in this tab.
  5. Download merged.pdf. There is no lock and no watermark.

People search “merge pdf” when they have a scan and a signed page, or two exports from different apps, and they need one attachment. That is this verb. Same tool lives at /pdf/merge if you want a merge-first URL.

How to split a PDF

  1. Choose Split. Drop one PDF. The page count is shown after the file is read locally.
  2. Type a range such as 1-3, 5 or 8-10. Pages are 1-based. all means every page in one file.
  3. Click Extract range to download those pages as a single PDF.
  4. Or click All pages as zip to get one single-page PDF per page, packed as a zip. If the zip step fails, download the pages one by one — the browser may ask you to allow multiple downloads.

Split is for pulling a cover letter out of a bundle, or turning a 20-page scan into 20 files. Direct URL: /pdf/split.

How to rewrite / “compress” a PDF

  1. Choose Compress. Drop one PDF.
  2. Click Rewrite PDF. We copy the pages into a new document and save with object streams.
  3. Read the before → after sizes. If the file grew, keep the original.

This will not match Smallpdf or ILovePDF. Those tools recompress the images inside the file, often aggressively. We do not. A phone scan of a paper form is already a pile of JPEGs — rewriting the wrapper barely moves the bytes. A messy Word or Pages export with leftover objects, unused fonts, and incremental updates often does shrink, and the result is a flatter file that other apps open more calmly. That is the useful case. Direct URL: /pdf/compress.

What this clinic does

The browser loads pdf-lib. Your files are read as ArrayBuffers, pages are copied, and a new PDF is built in memory. Close the tab and the bytes are gone. There is no Once server in this path, no queue, and no “free daily limit”.

A merge is a new file. Some form fields, comments, and scripts may flatten. That is often what you want before you send a packet to a landlord, a school, or a clerk. Encrypted PDFs stay closed — we will not ask for a password and we will not upload them “to unlock”.

Before you start — the honest limits

Keep the drop under about 80 MB total. Use a desktop. A 200-page scan can decode into a lot of memory even when the file itself looks small. If the tab reloads or goes white, the browser gave up. That is not a silent upload.

iPhone Safari is a bad host for this. Use a laptop. If you have hundreds of files, use qpdf, pdftk, or Preview on a machine you control. Once is for the two PDFs sitting in Downloads that you need as one attachment in the next minute.

What this is not

This is not a forms-as-a-service, not a resume builder, not a bank statement generator, and not an e-sign product. We will not add ads on the download or a Stripe wall. OCR, redaction, and image-recompress “real” shrink belong in other tools. Convert images (including HEIC) lives on /convert-image.

FAQ

Does the PDF leave my computer?

No. Merge, split, and rewrite run in this tab. The privacy page says the same thing.

Can I merge two scans for an application?

Yes. That is the usual “merge pdf” job. Drop both, order them, download one file, attach it. We do not store it.

Why did compress barely shrink my scan?

Because the weight is in the photos, and we do not recompress them. The note above the square is there on purpose. Use a dedicated compressor if you need Smallpdf-style ratios — and know that those services upload the file.

Do you add a watermark or ask for an email?

No. The download link is a normal file.

Is my job counted?

A successful merge, split, or rewrite increments a number in localStorage. Nothing is posted to a server.