MuPDF is a lightweight PDF viewer and toolkit written in portable C. The renderer in MuPDF is tailored for high quality anti-aliased graphics. MuPDF renders text with metrics and spacing accurate to within fractions of a pixel for the highest fidelity in reproducing the look of a printed page on screen. MuPDF has a small footprint. A binary that includes the standard Roman fonts is only one megabyte. A build with full CJK support is approximately five megabytes. MuPDF has support for all non-interactive PDF 1.7 features, and the toolkit provides a simple API for accessing the internal structures of the PDF document. Example code for navigating interactive links and bookmarks, encrypting PDF files, extracting fonts, images, and searchable text, and rendering pages to image files is provided.