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PPDF123

Merge PDF Files Online

Merge PDF combines two or more PDF files into one document, in the order you upload them. It joins the original pages with qpdf, so text stays selectable, and it needs no account.

Drag and drop files here, or click to choose

Accepts PDF · up to 500.0 MB per file

You can also paste a file with Ctrl/Cmd+V, or from the clipboard menu.

Merge concatenates PDFs into one file. A contract scanned page by page, a report that arrived as three exports, a stack of receipts that a portal will only take as a single attachment: those are the jobs.

The server calls qpdf with `--pages` and keeps each source's page streams. Text stays selectable. Fonts and page boxes travel with the pages. Bookmarks do not: the merged file has no outline, so rebuild it afterward if you need one. It does not print-to-PDF and rasterize everything into images.

On the website, page order is upload order. The form has no sort control. The API also accepts `sortType=byFileName`, which sorts by filename before concatenating. A request with one file is returned as that file; there is nothing to join.

On the website, each password-protected file asks for its password and is unlocked before the merge. Over the API, encrypted inputs fail until you Unlock them with a password you are entitled to use. Merge does not guess passwords.

There is no fixed file-count cap. Upload size and processing time are the limits. For a huge pack, merge small groups, then merge the intermediates.

If you only need some pages from each source, Extract Pages first, then merge the extracts. Merge itself has no per-file page range.

The result is an ordinary single-body PDF, not a PDF Portfolio container. Viewers, courts, and upload portals generally expect that shape.

The merged file has no bookmarks, because qpdf drops the outline of each source when it concatenates pages. Concatenation is not a tagged-PDF remediation suite; if accessibility tags matter, validate the output in your own checker.

Uploads are temporary and deleted when the result is ready. If policy forbids sending the files to a hosted service, self-host or use private infrastructure.

Features

  • Joins PDFs with qpdf `--pages` instead of reprinting them as images
  • Website order follows uploads; API can sort with `sortType=byFileName`
  • Anonymous API at /api/v1/general/merge-pdfs
  • Temporary processing; files are not kept as a library

When to use this tool

  • Assemble a contract and its scanned exhibits into one sendable PDF
  • Combine chapter exports from different tools into a single manuscript
  • Bundle receipts for expense software that accepts one file

How do I merge PDF files into one?

  1. Add every PDF you want in the combined file. On the website, upload order is page order.
  2. If a file is password-protected, this page asks for its password and unlocks it for you. API callers run Unlock first with a password they are entitled to use.
  3. Click Process. The server concatenates page streams; it does not re-render each page as an image.
  4. Download the combined PDF and check the page count before the next step.

Limits and edge cases

  • Password-protected files need the password; API callers run Unlock first
  • Bookmarks from the source files are not carried into the merged file
  • Very large batches take longer; merge in stages
  • Broken xref tables may need Repair before merge
  • Upload limit on this website: 500 MB per file, sent in chunks above about 95 MB. A single direct API request body is capped at 100 MB.

Examples

  • Uploading invoice-a.pdf then invoice-b.pdf yields A's pages, then B's
  • Merging three 10-page reports produces a 30-page PDF with each report's fonts intact

Privacy for this tool

Files are uploaded over HTTPS, processed in memory or a short-lived temporary directory on our servers, and deleted when your result is ready. We do not keep copies for later browsing, training, or advertising profiles. See the Privacy Policy for retention details and AdSense cookie disclosures.

Frequently asked questions

Does Merge follow upload order or filename?
The website uses upload order. The API uses that same order unless you set sortType=byFileName.
Does Merge flatten forms or annotations?
Widgets and annotations are carried when the PDF structure allows. Tangled AcroForm cases can still need Flatten afterward.
Is there a maximum number of files?
No fixed count. Upload size and processing time are the practical limits; merge large packs in stages.
What if I upload only one PDF?
You get that file back. Merge concatenates two or more inputs.

Last updated:

Call this from code

Every tool on this site is a plain REST endpoint - no account or API key needed for anonymous use. Built for AI agents and developers as much as for browsers.

curl -X POST "https://pdf123.xyz/api/v1/general/merge-pdfs" \
  -F "[email protected]" \
  -F "[email protected]" \
  -o output.pdf

Also available as an MCP tool for agent clients that speak Model Context Protocol (JSON-RPC 2.0 over POST /mcp). Full API reference

Use it from an AI agent

Skill

Claude Code, Codex, Cursor and other AI agents can run Merge for you with this skill: /skills/pdf123-merge.md

All agent skills

Files are used only for this processing job and deleted automatically afterward.