The OHIF Viewer reads CT, MR, PET, and slide microscopy studies straight from a DICOMweb archive and shows them in any browser tab, with no workstation software to install. The study list filters by patient name, MRN, study date, description, modality, and accession number. Each study launches into the workflow mode that fits its modalities. Basic Viewer mode tracks the measurements drawn on images and gathers them in a side panel for review. Layouts include MPR, four-up 3D, volume rendering, and PET/CT fusion with maximum intensity projection. Labelmap tools offer brush, eraser, threshold, and shape segmentation, and DICOM segmentation, RT Structure, and structured report objects display alongside the pixels. PDFs, video clips, ECG waveforms, 4D series, and whole slide microscopy open in the same interface. Hanging protocols arrange series the way each workflow expects. An iframe embed drops the viewer into a portal or research app. Pair it with Orthanc or DCM4CHEE for storage and Keycloak for sign-in. Oncology trial reads, imaging research, and web front ends for a PACS are the usual jobs. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.