How the Merger Logic Works
PDF merging is a low-level binary operation. Here is how the pdf-lib library processes your files:
Binary Loading: Each file is read as an
ArrayBuffer.Instantiation: The library creates a new "blank"
PDFDocument.Page Copying: Unlike simple text joining, PDF pages contain resources (fonts, images, forms). The
copyPagesfunction ensures that all these dependencies are correctly mapped from the source document to the new one.Serialization: The
save()method compiles the new page tree and generates the cross-reference table needed for the PDF to be valid and readable by software like Adobe Acrobat or Chrome.
Core Features
Responsive List: The file list uses Flexbox to stay organized on mobile. It truncates long filenames so the UI doesn't break.
Safety First: Since the merger happens in the
Blobmemory of the browser, no data is ever transmitted to a server.Validation: The "Merge" button only activates when at least two files are added, preventing logic errors.
PDF Merger
Combine multiple PDF files into one, securely in your browser.
Click to add PDFs
or drag and drop files here