WebPDF: a browser-based software application for calculating X-ray pair distribution function

Pair distribution function (PDF) analysis based on X-ray total scattering is a powerful technique for elucidating local and medium-range structure in crystalline, nanocrystalline, and amorphous materials. Several software packages-such as GudrunX, PDFgetX2, and PDFgetX3-along with facility-specific programs developed at synchrotron sites, are widely used for this purpose. However, these tools typically require installation and environment-dependent configuration, which can introduce compatibility issues across operating systems and create conflicts with pre-installed software. To overcome these limitations, we developed a browser-based PDF analysis application implemented using Pyodide and PyScript, allowing it to run entirely in modern web browsers without additional installation. The software provides key functionalities, including Fourier transformation from S(Q) to G(r), calculation of g(r), back-Fourier transformation with cutoff handling, and sequential data processing. Demonstrations on representative samples confirm consistency with established programs. The software supports both synchrotron data and laboratory-based measurements using Ag radiation sources, underscoring its broad applicability. This tool enables environment-independent and consistent analyses, significantly enhancing the accessibility of X-ray total-scattering and PDF techniques.