Workflow of PII (discussed in detail in Sect. 3.3). This is the part of TUVOpipe that searches for transient candidates in UVOT images through difference image analysis. The operation of PII is identical for the real-time and archival modes, since in archival mode it simply stops after the field of interest is completed. When PII terminates, it has produced lists of candidate transients for each field and filter. These are passed to Part III of the pipeline (see Sect. 3.4), which is automatically initiated upon completion of PII.