Pfam is a comprehensive database of protein families, currently containing 7973 entries (release 18.0). A recent development has been the grouping of related families into clans, which are defined by up to four pieces of evidence: related structure, related function, significant matching of the same sequence to HMMs from different families, and profile-profile comparisons. Pfam clans help improve family annotation and provide a hierarchical view of protein families. The paper describes the new web tools and services available for accessing Pfam, including domain images, HMM logos, colored alignments, domain query tools, and web services for automated searches and UniProt sequence annotation. These tools enhance the functionality and accessibility of Pfam, making it a valuable resource for genome annotation and protein family analysis.Pfam is a comprehensive database of protein families, currently containing 7973 entries (release 18.0). A recent development has been the grouping of related families into clans, which are defined by up to four pieces of evidence: related structure, related function, significant matching of the same sequence to HMMs from different families, and profile-profile comparisons. Pfam clans help improve family annotation and provide a hierarchical view of protein families. The paper describes the new web tools and services available for accessing Pfam, including domain images, HMM logos, colored alignments, domain query tools, and web services for automated searches and UniProt sequence annotation. These tools enhance the functionality and accessibility of Pfam, making it a valuable resource for genome annotation and protein family analysis.