How to Merge PDF Files
Combining multiple PDF documents into a single file is a common task, but it shouldn't require uploading your sensitive data to unknown servers. With Andromeda PDF, you can merge your files right here in your browser.
Select Your Files
Click the "Select PDF Files" button or drag and drop your documents into the upload area. You can select multiple files at once from your computer.
Reorder Pages
Once uploaded, you'll see a list of your files. The order they appear in the list is the order they will appear in the final document. If you need to change the sequence, simply remove files and re-add them in the correct order (drag-to-reorder coming soon!).
Merge and Download
Click the "Merge PDFs" button. The in-browser engine will stitch your documents together instantly. Once complete, a "Download" button will appear. Save your new file to your device!
Why Client-Side Merging is Safer
Most online PDF tools work by uploading your files to their cloud servers. This means your data travels across the internet, is stored (temporarily or permanently) on someone else's computer, and is then processed and sent back to you.
Andromeda PDF Difference: We use advanced browser technologies to run the PDF processing code directly on your device. Your files never leave your computer.
This implies two major benefits:
- Privacy: No one, not even us, can see your files. They remain 100% private.
- Speed: You don't have to wait for large files to upload or download. The processing happens instantly.
Technical Insight: Under the Hood
Unlike server-side tools that process your files on a remote machine, Andromeda PDF runs pdf-lib — a mature open-source PDF engine — directly inside your browser's JavaScript runtime. The code that touches your document executes on your CPU, not ours.
When you click "Merge", we stream the file buffers into this isolated local memory space, stitch the objects, and regenerate the Cross-Reference Table (XRef) without a single byte ever transmitting over the network.
Common Use Cases
For Business
Combine invoices, receipts, and reports into a single monthly packet for your accountant.
For Students
Merge lecture notes, assignment criteria, and your essay into one submission file.
For Job Hunters
Stitch your Cover Letter, CV, and Portfolio together so recruiters only have to open one file.
For Legal
Compile evidence documents and contracts securely without violating client confidentiality.