PDF Overlay

The 'PDF Overlay' tool is a specialized utility for combining two PDF files by layering one on top of the other. The most common use case is applying company letterheads (paper designs with company names and logos) to existing PDF documents. For example, you can prepare a letterhead design as a PDF, overlay it onto a text document PDF, and instantly create a PDF that looks as if it was printed on letterhead paper.

This tool provides two composition modes for flexibility. In 'Repeat First Page' mode, the first page of the overlay PDF is repeated on every page of the base PDF. This is ideal for applying the same design — such as a letterhead or watermark — to all pages uniformly. In 'Match Pages' mode, each page of the overlay PDF is layered onto the corresponding page of the base PDF in a one-to-one mapping. This is useful when you want to apply different designs or stamps to individual pages. If the overlay PDF has fewer pages than the base PDF, the remaining base pages will have no overlay applied.

For security and privacy, all processing happens entirely within your browser — no data is ever uploaded to any server, making it completely safe for confidential documents, personal records, and sensitive business files. Using the pdf-lib library for high-precision page composition, the tool maintains the quality of fonts and images from the original PDFs while producing beautifully overlaid results.