Welcome to ac4C Info database. ac4C Info is a database platform dedicated to collecting N4 acetylytidine (ac4C) modifications in RNA from all species. At present, it is the first version, mainly consisting of four parts:the ac4CDB database, which includes the ac4C modification site information identified by ac4C-seq single base resolved detection technology for ac4C RNA acetylation modification, and the distribution area information of ac4C in the transcriptome analyzed by acetylated RNA immunoprecipitation (acRIP-seq) technology; The ac4CDiseaseDB database contains germline variations extracted from dbSNP, 1000 Genomes, and Ensembl, as well as disease related ac4C SNPs (involving the addition or loss of ac4C sites) identified from somatic variations of 33 different human cancer types collected from the Cancer Genome Atlas (TCGA); And two analysis modules for real-time interactive analysis of ac4C modification site prediction (ac4C Predictor) and evaluation of the impact of genetic variation on ac4C modification (ac4C SNP IFer). We hope that ac4C Info can become a comprehensive and valuable resource platform for sharing, centralizing, annotating, and customizing analysis of ac4C data.