UniProt is a comprehensive, expert-led, publicly available database of protein sequence, function, and variation information.This webinar will give a brief introduction to the UniProt website and then highlight resources available that proteomics scientists or users with large protein datasets may find useful in analysing their data. This will encompass our proteomes service, how to convert and retrieve ID mappings, how to carry out a peptide search and how to visualise new large scale proteomics-derived PTM data.The webinar will then go on to introduce the UniProt Proteins API which allows researchers to access and download UniProt data alongside large-scale genomic, proteomics and variation data without needing prior in-depth knowledge of programmatic languages. Data is available for download and querying in a range of formats, including XML, FASTA, and PEFF. The API multi-query search functions will be demonstrated and useful features such as searching the database by peptide, finding proteomic evidence of post translational modifications and accessing a protein entry to find its peptides will be explained.The UniProt Proteins API is available at //www.ebi.ac.uk/proteins/api/doc